Quick answer: Business texts to US numbers usually stop sending for one of seven reasons: an unregistered 10DLC number, an unverified toll-free number, content filtering, a recipient who replied STOP, a landline or dead number, a volume cap, or the wrong kind of sending number. Twilio has blocked unverified toll-free texts since 31 January 2024. Diagnose by width: every message, one carrier, one person, one kind of message, or only at busy times.
This is a symptom-first triage for anyone texting customers from a business number, whether in a phone-system app such as RingCentral, Dialpad, Quo (formerly OpenPhone) or Google Voice, or through a messaging API such as Twilio. It covers US carriers (AT&T, T-Mobile, Verizon), A2P 10DLC registration with The Campaign Registry, toll-free verification, the CTIA Messaging Principles and Best Practices, and each platform’s error codes, every one linked to the publisher’s own page as read on 12 November 2026. If you text Australian mobiles under an alphanumeric sender name, different rules apply; see Australia’s SMS Sender ID Register for AI outreach.
Where Zian fits when business texts stop sending
Zian is an AI sales and reception agents platform whose agents follow up by SMS as one channel among voice calls, email, WhatsApp, Instagram DMs and Facebook Messenger, so a follow-up plan does not have to hang on one text getting through. Zian does not exempt anyone from 10DLC registration, toll-free verification or carrier filtering, and it promises no delivery rate: every rule on this page applies to automated texts, including an AI agent’s.
SmartReach AI™ orchestrates the message, channel and timing of follow-up, and Zian’s AI Receptionist answers inbound calls 24/7, for the customer who never saw your text and rings back. Zian is in a partnership-application beta; each of its three listed plans, including Intel + Widgets (Free Forever), starts with a partnership application. To hand the whole job over, LeadsNow.ai is the done-for-you option: a pay-per-result managed appointment-setting service that runs on Zian.
Want AI agents that follow up by call, text, email and WhatsApp? Zian is in a partnership-application beta. Apply For Partnership
Why are my business SMS messages not sending?
A failed business text was stopped by your platform, its upstream carrier, the recipient’s carrier, or the handset. RingCentral’s error codes make the split explicit: they start with SMS-RC- when RingCentral itself stopped the message, SMS-UP- when the upstream provider did, and SMS-CAR- when the recipient’s wireless carrier did, per RingCentral’s SMS error page.
The first thing to work out is not the error code but how wide the failure is. Every message points to your number or account; one carrier points to filtering or a carrier limit; one person points to their number or their opt-out; one kind of message points to what it says.
The quotable version: the width of an SMS failure tells you its cause faster than the error code does, because the same cause carries a different code on Twilio, RingCentral, Bandwidth, Quo and Google Voice.
The Blast-Radius Ladder: how wide is the failure?
We call this triage the Blast-Radius Ladder. Start at the top rung and stop at the first one that matches what you see.
| Rung: what you see | Most likely cause | Test that tells the causes apart | First fix |
|---|---|---|---|
| 1. Every text to US numbers fails, from the first day or since a change | Number not registered to an approved 10DLC campaign; toll-free number not verified; account out of credits or blocked | Check registration or verification status in your admin settings; check the number type (local or toll-free) | Finish 10DLC registration or toll-free verification, and confirm this number is attached to the approved campaign |
| 2. Texts to one carrier fail (for example, only T-Mobile customers) | That carrier’s spam filter; your brand’s T-Mobile daily cap; the recipient’s plan blocks toll-free or short-code texts | Group failed messages by recipient carrier and by time of day | Fix content and consent; spread volume; if it is the daily cap, wait for the reset or apply for a higher tier |
| 3. One person never gets your texts | They replied STOP (or END, CANCEL, QUIT, UNSUBSCRIBE); the number is a landline, invalid or deactivated | Search your inbound history from that number for an opt-out word; look up the line type | Ask them to text START or UNSTOP; otherwise call or email instead |
| 4. Only some messages fail, and they share a feature | Content filtering: public link shorteners, links, carrier names, prohibited topics, one-word “Hi” or “Test”, long or emoji-heavy bodies | Resend the same message without the link, the brand or carrier name, or the emoji; compare | Use a branded domain you own, identify your business, keep STOP wording, drop prohibited content |
| 5. Texts fail only at busy times or late in the day | Per-minute or daily volume limits on your registered brand or campaign | Do failures cluster after a burst, then clear after a reset? | Queue and pace sends; review your throughput tier |
| 6. Status says “Delivered” but the customer never saw it | A device problem (one person) or filtering reported as delivered (many people) | One device or many? | One: check the handset. Many: treat it as rung 2 or 4 |
Rung 1: every text fails, so the number is not cleared to send
If nothing goes out to US numbers at all, your number has not been cleared by the carriers. For a local 10-digit number that means A2P 10DLC registration: your brand and campaign approved through The Campaign Registry, and the number attached to that campaign. For a toll-free number it means toll-free verification.
The vendors are blunt about this. Quo’s carrier-registration page says that “as of August 31, 2023, unregistered numbers cannot text US phone numbers”, that registration applies even to personal use, that you cannot message US numbers while approval is pending, and that registration is not available during a free trial (“only paid Quo customers can complete carrier registration”). RingCentral’s SMS requirements page says “only phone numbers that are linked to an active, approved campaign will be enabled for SMS messaging” and that toll-free numbers “must be verified” to enable SMS. Dialpad’s A2P registration FAQ answers “Can I send SMS while registration is pending?” with “No”. Dialpad’s Campaign Registry FAQ adds that Dialpad-to-Dialpad messages are not affected, which is why internal texts can keep working while texts to customers fail.
On Twilio, error 30034 means a +1 10DLC number “not associated with an approved A2P 10DLC Campaign”, including a number left out of the Sender Pool or a second number on a Sole Proprietor campaign, which can register only one. Error 30035 means the number is still being configured (Twilio says “allow up to 24 hours”). Error 30032 is the unverified toll-free block, in force “as of January 31, 2024”.
Account-level causes look the same from outside. Dialpad says an account out of credits “won’t be able to send or receive external SMS or MMS messages until credits are added”, and a deactivated and reactivated account must register its campaign again. RingCentral’s SMS-UP-414 and SMS-CAR-414 mean the number is not set up to send texts.
Approved, but some numbers still fail. Quo’s Messaging issues page describes a “Destination Not Found” error after approval. Its explanation is that approval “can apply at the campaign level before it fully propagates to every number on the account” and that carriers “can take 24-48 hours after approval to fully update their routing tables”. How long registration itself takes is set out in how long A2P 10DLC registration takes. For toll-free, see how long Twilio toll-free verification takes.
Rung 2: texts to one carrier fail, so it is filtering or a carrier limit
When texts reach Verizon and AT&T customers but not T-Mobile customers, or the reverse, your registration is probably fine and that carrier is objecting to your traffic. Twilio’s article on SMS filtering in the United States and Canada says carriers “use machine learning software systems to filter messages”, scoring each one on how much a number has sent, how many similar messages have crossed the network, and whether the content resembles spam. In Twilio’s experience, “high opt-out rates and end user complaints also play a major role”.
It can also be a cap rather than a filter. Twilio error 30023 says the T-Mobile daily limit applies per brand (per EIN), counts SMS segments and MMS sent to T-Mobile, Sprint and MetroPCS “across any messaging platform you have registered your Brand with”, is based on your Brand Trust Score, and resets at 00:00 US Pacific time. RingCentral reports it as SMS-CAR-450 (T-Mobile, per brand) or SMS-CAR-451 (AT&T, per campaign), and Bandwidth as 4780.
One more carrier-specific cause catches toll-free senders. Bandwidth’s description of error 4720 says that, for toll-free messages to T-Mobile, it “could also mean the user has opted to block all toll free and short code traffic”. That failure is about the recipient’s setting, not your content.
Rung 3: one person never gets your texts
When one contact fails and everyone else is fine, ask two things: did they opt out, and can their number take a text?
They opted out, perhaps without meaning to. Twilio error 21610 blocks a number that replied STOP “until the subscriber identified by the phone number has responded with ‘START’”, and lists a second cause: the number “has been reassigned to a different end user recently”. Quo’s opt-out page lists six single-word keywords (STOP, STOPALL, UNSUBSCRIBE, CANCEL, END, QUIT), says “STOP PLEASE” will not trigger one, and says an opt-out “applies to all Quo numbers associated with your account”. So a customer who once replied with the single word END has opted out of your whole Quo account. Quo keeps no master opt-out list; the sign is a “Failed” status in that thread.
RingCentral’s High Volume SMS opt-out page lists STOP, UNSUBSCRIBE, QUIT, CANCEL and END, handled “per pair of sender and recipient numbers”. Either way, only the person can reverse it, by texting START or UNSTOP. If they did and still get nothing, Dialpad’s advice is to check their phone’s blocked and spam settings, unblock your number, then text UNSTOP.
Their number cannot take a text. Twilio error 30006 covers landlines, which “generally cannot receive SMS messages”; Twilio’s fix is to look up the line type and not retry. Error 30005 means the number “is unknown and may no longer exist”, and 21614 means it is not a valid mobile number. The other platforms’ codes are in the crosswalk below. The CTIA Messaging Principles and Best Practices (May 2023 edition) ask senders to “process telephone deactivation files regularly (e.g., daily)” and remove deactivated numbers from opt-in lists. That habit stops dead numbers before they fail.
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Rung 4: only some messages fail, and the words are the trigger
If one number delivers some messages and loses others, compare what the failed ones share. Triggers the vendors name:
- Public link shorteners. Twilio’s article on sending shortened links says not to send links shortened with shared public shorteners such as free TinyURL or Bitly, which carry “higher risk of filtering, with no recourse if filtering does occur”; use a domain your business owns that matches the sender named in the text. RingCentral has a dedicated code (SMS-CAR-435), as does Bandwidth (4771). CTIA asks for “a web address and IP address(es) dedicated to the exclusive use of the Message Sender”.
- Carrier names. Dialpad’s Campaign Registry FAQ says carriers “like Verizon and T-Mobile often block messages that include their names”. A text telling a customer to “check your T-Mobile signal” can fail for that reason alone.
- One-word tests. Dialpad says short messages like “Hi” or “Test” are blocked because they “lack context and are flagged as high-risk by automated filters”. If your test message failed and your real messages go through, this is why.
- Prohibited topics. Dialpad and Quo both bar high-risk financial services, debt relief, cannabis and CBD, and SHAFT content (sex, hate, alcohol, firearms, tobacco), with exceptions such as age-gated alcohol messaging on Quo. Dialpad’s content compliance page says T-Mobile charges Severity Zero fees, billed through Dialpad: $2,000 for phishing, smishing and social engineering, $1,000 for illegal content, $500 for other violations including SHAFT.
- Length and characters. RingCentral’s SMS-CAR-432 says some carriers do not support joined-up (concatenated) messages and suggests cutting the text to 160 characters. Dialpad’s Send a Message page says that with emojis or special characters the per-page count drops from 160 to 63.
- Missing identity and opt-out wording. Quo’s deliverability page asks that the first message identify the sender and say “Reply STOP to unsubscribe”. It also warns against “SIGN UP NOW FREE”-style marketing language and identical messages to large groups.
On Twilio a content block shows as 30007 (“filtered (blocked) by Twilio or by the carrier”); the other platforms’ codes are in the crosswalk below. One sentence on Quo’s own page cuts against all of this advice: “Carrier filtering can be overly aggressive.” A compliant message can still be filtered, and Quo’s answer is to send support your opt-in process, use case and example messages. If an AI agent writes your texts on Twilio and the failures are 30007s, the deeper test is in why AI SMS gets filtered and what error 30007 means.
Rung 5: texts fail only at busy times, so you hit a volume cap
A failure that starts after a burst and clears on its own is a limit, not a ban. Dialpad’s A2P FAQ gives the range for registered 10DLC traffic. The lowest tier allows 2,000 messages a day to T-Mobile and 75 SMS a minute on AT&T. The highest allows up to 200,000 a day to T-Mobile and 4,500 a minute on AT&T. Sole Proprietor brands get one number and lower limits. Quo says sole proprietors “may see a cap for number of messages you can send per day”, shown in the A2P dashboard.
On Twilio, 30022 is the per-campaign rate limit and 30023 the daily cap. 30027 warns that you have used 100% of your T-Mobile limit, though Twilio says it “may not be accurate” for some customers, such as those on an unlimited tier or running non-profit campaigns.
Can I send business texts from Google Voice?
For one-to-one conversations, yes; for anything automated or bulk, Google says no. Its help page on texting says Voice messaging “is intended only for interactive conversations” and “is not intended for bulk messaging”. Behaviours it may block include, but are not limited to, the same text to several recipients, URL links, and many texts in a short time; the error reads “Message not delivered. You’ve sent too many messages.” The first stage is a temporary block (“wait 24 hours and try again”); repeating the behaviour, or behaviour that needs immediate intervention, leads to suspension. Google’s Voice Acceptable Use Policy bans “sending messages via an automated process, such as a script”. The help page also says you cannot text five- or six-digit short codes, and that texts from a recently ported number might not work “until 3 business days after your transfer finishes”. For reminders or follow-ups sent by software, Google Voice is the wrong sending number: cause seven.
“Delivered” but the customer never got it
A “Delivered” status is the carrier’s report, not proof the message reached the phone. Twilio’s article on Delivered messages that are not showing up says false positives to one device are “likely caused by a device-specific issue”, while false positives to multiple users can come from carrier filtering, local telecom infrastructure or technical limitations. RingCentral’s SMS-CAR-199 says the message “may have been delivered, but the carrier did not return a status confirmation”. Quo calls the many-recipient pattern “soft-blocking”.
The test is breadth again: one customer means their handset, blocked list or spam folder; several in the same week means rung 2 or rung 4. As RingCentral’s guide puts it, a successful send request “does not guarantee that the messages will be delivered”.
The error-code crosswalk: the same seven causes on five platforms
Keep this table open while you read a failure log. Each cell is the code or on-screen message that platform documents for that cause, as at 12 November 2026. The Bandwidth column gives the four-digit codes on Bandwidth’s messaging API error page. Dialpad’s A2P FAQ instead points customers to Bandwidth’s SMPP error-code support page; in Bandwidth’s SMPP and MM4 error codes article the same causes carry three-digit codes: 476 (unregistered 10DLC), 795 (unverified toll-free), 470, 770 and 771 (filtering), 475 and 775 (opt-out), 720 and 721 (invalid or deactivated number), 780, 781 and 785 (volume) and 433 (toll-free messaging not enabled).
| Cause | Twilio | RingCentral | Bandwidth messaging API | Quo (on-screen) | Google Voice (on-screen) |
|---|---|---|---|---|---|
| 1. Unregistered 10DLC number | 30034; 30035 (still configuring); 30024 (not yet provisioned) | SMS-UP-414, SMS-CAR-414 (number not set up to send texts) | 4476 (source number not registered to a 10DLC campaign) | “Destination Not Found” while approval propagates; Pending status under Settings, Trust | Google’s texting help page limits Voice to interactive messaging instead |
| 2. Unverified toll-free number | 30032 | SMS-CAR-461 | 4795 | Outbound texts to US and Canadian numbers blocked | Not covered on the texting help page we read |
| 3. Spam or content filtering | 30007 | SMS-RC-430, SMS-UP-430, SMS-UP-431 (number flagged for spam), SMS-UP-433, SMS-CAR-430, SMS-CAR-435 (shortened URL) | 4470, 4770, 4771 (shortened URL) | “Content flagged against carrier guidelines” | “Message not delivered. See Acceptable Use Policy.” |
| 4. Recipient opted out | 21610 | SMS-RC-413, SMS-UP-413, SMS-CAR-413 | 4475, 4775 | “Failed” status in the thread | Not listed on the help page we read |
| 5. Landline, invalid or dead number | 30006, 30005, 21614 | SMS-RC-410, SMS-UP-410, SMS-CAR-400, SMS-CAR-411, SMS-CAR-412 | 4720, 4721 | “Unable to receive message – landline or unreachable”; “Destination number unknown or no longer exists” | Not listed on the help page we read |
| 6. Volume cap | 30022, 30023 (30027 is the warning) | SMS-RC-403, SMS-CAR-450, SMS-CAR-451, SMS-CAR-452 | 4780 (T-Mobile), 4781 (AT&T), 4785 | Sole Proprietor daily cap shown in the A2P dashboard | “Message not delivered. You’ve sent too many messages.” |
| 7. Wrong sender or number type for the destination | 21612 (To/From combination not allowed); 30024 (destination recently ported) | SMS-CAR-460 (short code; RingCentral does not support short codes) | 4720 (T-Mobile user blocks toll-free and short-code traffic); 4433 (toll-free messaging not enabled) | SMS after porting may take 24–48 hours | Cannot text 5–6 digit short codes; texts from a ported number may wait 3 business days |
Read the table by row, not by column. A RingCentral SMS-CAR-430, a Bandwidth 4770 and a Twilio 30007 are the same problem and get the same fix.
The seven causes, the fix, and how long each takes
Waits are quoted in each vendor’s own words. Where a vendor says “most” or “may”, so does this table.
| Cause | Fix | Typical wait, in the vendor’s words |
|---|---|---|
| 1. Unregistered 10DLC number | Register brand and campaign; attach the sending number to the approved campaign | Quo: “Most approvals happen within 24-48 hours”, some pending “up to 20 days”, rarely “longer than 30 days”; the FAQ on the same page says “Processing varies from 5-7 business days to 30+ days depending on review backlog”. Dialpad: “~3 weeks”, which “could increase due to an uptick in volume”. Twilio: up to 24 hours for number registration after approval |
| 2. Unverified toll-free number | Submit toll-free verification; send nothing from the number until approved | Quo: “may take 2-3 weeks to process once the information has been correctly provided” |
| 3. Spam or content filtering | Branded links, sender identity, STOP wording, no carrier names or prohibited topics; send examples to support if compliant | No published wait: it clears when the content or pattern changes. Google Voice: “wait 24 hours” after a temporary block |
| 4. Recipient opted out | The recipient texts START or UNSTOP | Quo: delivery resumes “immediately” after opt-back-in |
| 5. Landline, invalid or dead number | Look up the line type; stop retrying; call or email instead | None: the number will not start taking texts |
| 6. Volume cap | Pace and queue sends; review your throughput tier | Twilio: the T-Mobile daily limit resets at 00:00 US Pacific time |
| 7. Wrong sender or number type | Use a registered local or verified toll-free number for business texting; wait out a port | Quo: 24–48 hours after a port. Google Voice: up to 3 business days after a port |
Two of the seven, the unregistered number and the unverified toll-free number, are the ones with a registration queue. The other five have no registration queue.
What fixing this yourself costs
For a small team texting by hand, everything above can be done in-house. Registration fees are small: Quo lists a one-time $19.50 fee “paid directly to the Carrier Registry on your behalf”, $1.50 a month for most organisations ($3 for non-profits, $2 for sole proprietors), and $15 to resubmit; its toll-free registration is included in the subscription. The ongoing work is what costs time:
- Someone owns the registration: legal name and EIN matching tax records, a live website with opt-in wording, and sample messages that match what staff and software actually send.
- Someone reads failures weekly against the crosswalk above.
- Opt-outs are synced everywhere you text from, since Quo applies them account-wide and RingCentral’s High Volume SMS per number pair.
- Volume is paced to your tier, so a busy Monday does not run into the T-Mobile daily cap.
Our rule of thumb: one or two people texting from a shared inbox need a monthly check; software sending reminders and follow-ups at volume needs a deliverability check on every change to wording, timing and lists.
Frequently asked questions
Why are my business text messages not sending?
Usually one of seven causes: an unregistered 10DLC number, an unverified toll-free number, content filtering, an opt-out, a landline or dead number, a volume cap, or the wrong sending number. If every message fails, check registration first: RingCentral’s SMS requirements say only numbers linked to an active, approved campaign are enabled for SMS.
Why are my texts failing to only one person?
Usually they opted out or their number cannot take texts. A reply such as STOP or END blocks you until they text START or UNSTOP, and Quo’s opt-out page says the block covers every Quo number on your account.
Can I send texts while my 10DLC registration is pending?
No, not to US numbers. Dialpad’s A2P registration FAQ answers this with “No”, and Quo agrees. Quo’s registration page says most approvals take 24–48 hours and some stay pending for up to 20 days, while the FAQ on the same page gives 5–7 business days to 30+ days depending on review backlog.
Why do my texts fail to T-Mobile customers but not to Verizon or AT&T?
Either T-Mobile’s filter is scoring your traffic as unwanted, or your brand has hit its T-Mobile daily limit. Twilio error 30023 says that limit applies per brand (per EIN) across every platform you registered with and resets at midnight US Pacific time.
Can I put a bit.ly link in a business text?
Avoid it. Twilio’s article on sending shortened links says not to send links shortened with shared public shorteners such as free TinyURL or Bitly links, which carry “higher risk of filtering, with no recourse if filtering does occur”, and recommends a short domain your business owns that matches the sender named in the text.
Why does my text say delivered when the customer never got it?
Twilio’s article on Delivered messages says a false positive to one device is likely a device problem, while false positives to many people can come from carrier filtering, local infrastructure or technical limits.
Can I use Google Voice to send automated business texts?
No. Google’s Voice help page says Voice messaging is intended only for interactive conversations, not bulk messaging, and Google’s Acceptable Use Policy bans sending messages via an automated process such as a script.
Where every figure on this page comes from
Every source below was read on 12 November 2026. We read Dialpad’s and Twilio’s help-centre articles through each help centre’s public article API (Dialpad’s site blocks automated page fetches); the links go to the public pages. RingCentral’s support-site articles did not load for our reader, so RingCentral facts come from its developer guide.
| Figure | Who published it | Link | Date read |
|---|---|---|---|
| Unregistered numbers cannot text US numbers as of 31 August 2023; can’t message US numbers while pending; most 10DLC approvals within 24–48 hours, some pending up to 20 days, rarely over 30 days; FAQ: 5–7 business days to 30+ days; registration only for paid customers, not during a free trial; $19.50 one-time, $1.50 / $3 / $2 monthly, $15 resubmission; sole-proprietor daily cap | Quo | support.quo.com carrier registration | 12 November 2026 |
| Toll-free verification may take 2–3 weeks; unregistered toll-free texts to US and Canadian numbers blocked | Quo | support.quo.com toll-free registration | 12 November 2026 |
| Six single-word opt-out keywords; opt-out covers all Quo numbers on the account; START or UNSTOP to resubscribe; delivery resumes immediately; no master opt-out list | Quo | support.quo.com message opt-out | 12 November 2026 |
| On-screen error names; “Destination Not Found” and 24–48 hours for routing after approval; 24–48 hours after a port; soft-blocking causes | Quo | support.quo.com messaging issues | 12 November 2026 |
| No generic shorteners; “Reply STOP to unsubscribe”; “Carrier filtering can be overly aggressive”; alcohol exception with age verification | Quo | support.quo.com message deliverability | 12 November 2026 |
| Error-code prefixes SMS-RC / SMS-UP / SMS-CAR and every RingCentral code on this page; 160-character advice; check again after an hour; API success does not guarantee delivery | RingCentral | RingCentral developer guide, SMS errors | 12 November 2026 |
| Only numbers linked to an active, approved campaign are SMS-enabled; toll-free numbers must be verified | RingCentral | RingCentral developer guide, SMS requirements | 12 November 2026 |
| High Volume SMS opt-out keywords; opt-out handled per sender and recipient number pair | RingCentral | RingCentral developer guide, opt-in / opt-out | 12 November 2026 |
| Can’t send while pending; credits; re-register after reactivation; volume tiers 2,000/day and 75/minute up to 200,000/day and 4,500/minute; “Hi” and “Test” blocked; error codes on Bandwidth’s SMPP error-code page; approval does not guarantee delivery | Dialpad | Dialpad A2P SMS Registration and Compliance FAQs (updated 29 October 2026) | 12 November 2026 |
| Registration ~3 weeks; carriers block messages naming Verizon or T-Mobile; Dialpad-to-Dialpad unaffected | Dialpad | Dialpad Text Message Campaign Registry FAQs (updated 9 October 2026) | 12 November 2026 |
| Severity Zero fees of $2,000, $1,000 and $500, charged by T-Mobile and billed through Dialpad | Dialpad | Dialpad SMS Content Compliance | 12 November 2026 |
| 160 characters per page, 63 with emojis or special characters | Dialpad | Dialpad Send a Message | 12 November 2026 |
| Codes 4433, 4470, 4475, 4476, 4720, 4721, 4770, 4771, 4775, 4780, 4781, 4785, 4795 | Bandwidth | Bandwidth API docs, messaging errors | 12 November 2026 |
| SMPP codes 433, 470, 475, 476, 720, 721, 770, 771, 775, 780, 781, 785, 795 | Bandwidth | Bandwidth Help Center, SMPP and MM4 error codes | 12 November 2026 |
| 30034, 30035 (up to 24 hours), 30024 | Twilio | 30034, 30035, 30024 | 12 November 2026 |
| 30032: unverified toll-free traffic blocked as of 31 January 2024 | Twilio | twilio.com error 30032 | 12 November 2026 |
| 30007 filtered; 21610 opted out (and reassigned numbers); 30006 landline; 30005 unknown number; 21614 not a valid mobile; 21612 To/From combination | Twilio | 30007, 21610, 30006, 30005, 21614, 21612 | 12 November 2026 |
| T-Mobile daily limit per brand (per EIN), across platforms, reset at 00:00 Pacific; 30022 rate limit; 30027 100% warning and its accuracy caveat | Twilio | 30023, 30022, 30027 | 12 November 2026 |
| Carrier machine-learning filtering factors; opt-out rates and complaints “play a major role” | Twilio | SMS Message Filtering in the United States and Canada | 12 November 2026 |
| Public shorteners: “higher risk of filtering, with no recourse” | Twilio | Sending Shortened Links in Your Messages | 12 November 2026 |
| Delivered false positives: one device vs many users | Twilio | Delivered but not showing up | 12 November 2026 |
| Interactive use only; “You’ve sent too many messages”; 24-hour block then suspension; no short codes; US, Canada and Puerto Rico; group texts up to 7 others; 3 business days after a port | Google Voice Help, send and get text messages | 12 November 2026 | |
| Ban on automated messages sent by script | Voice Acceptable Use Policy | 12 November 2026 | |
| Opt-out wording (5.1.3), daily deactivation files (5.1.5), dedicated shortener domain and IP (5.3.2) | CTIA | Messaging Principles and Best Practices, May 2023 | 12 November 2026 |
| Zian channels, SmartReach AI™, AI Receptionist, plan names | Zian (first party) | zian.ai | 12 November 2026 |