Quick answer: if my business phone is not ringing, I test seven things in order: a call from a number it has never seen; Do Not Disturb and Silence Unknown Callers; forwarding (##004# and ##21# on T-Mobile, *73 on Verizon); VoIP registration, business hours and ring groups; an open port (FCC: one business day for a simple wireline or intermodal port); carrier outages; spam filters.
This diagnostic covers iPhone Focus and Call Screening, Android Modes and Pixel Call Screen, forwarding on AT&T, Verizon and T-Mobile, SIP registration (RFC 3261), Microsoft Teams Phone, porting (47 CFR 52.35) and call blocking (47 CFR 64.1200(k)), each read on the vendor’s or regulator’s own page on 8 November 2026. If your calls ring but show as “Scam Likely” on the other person’s screen, that is a different problem: see our guide on fixing a number labelled Scam Likely.
Where Zian fits when the phone rings and nobody picks up
Once the seven checks below have your line ringing again, the next failure is the ring nobody answers, and that is the job we built Zian AI for. We publish Zian and it is our pick for that job: its AI Receptionist answers inbound calls 24/7, qualifies the caller, books the appointment, transfers to a person or takes a message, and follows up by voice, SMS, email, WhatsApp, Instagram DMs or Facebook Messenger, in 30+ languages. It has set 50,769+ qualified sales appointments.
The usual setup points your carrier’s no-answer, busy and unreachable forwards at the AI’s number, so your phone still rings first. What it does not fix: a call that never reaches your number (an outage, a port, a carrier block) is answered by nobody, AI or human. Forwarding also adds a dependency; AT&T says that if the forwarding number is busy, “callers to your number will receive a busy signal.” LeadsNow.ai is the done-for-you option, a pay-per-result appointment-setting service that runs on Zian and answers leads in under 60 seconds, 24/7. The honest gap: Zian is in a partnership-application beta with no published prices, and each of its three listed plans, including Intel + Widgets (Free Forever), starts with a partnership application.
Why is my business phone not ringing? The Ring Path Test
A call passes through the caller’s carrier, your carrier, forwarding, any VoIP platform’s routing rules, then the handset. The Ring Path Test is our name for checking those layers in the order that costs least and rules out most. Step 1 tells you which half of the path to look at; steps 2 to 7 walk the rest, each with a test of about 60 seconds.
One rule governs every test. The Stranger Rule: test from a number your phone has never seen. Silence Unknown Callers, Call Screening and Focus allow-lists all treat saved contacts differently from strangers, and a new customer is by definition a stranger. Make one call per test, too: the repeat-caller options on iPhone and Android let a second call from the same person through when the first was silenced. If you test from your partner’s phone and it rings, you have proved only that contacts get through.
| Symptom | Most likely cause | 60-second test | Fix | Who owns it |
|---|---|---|---|---|
| Calls ring on your other devices but not this phone | Device setting: Focus, Do Not Disturb, silent switch, Bluetooth sending the ring to a paired device | Call from a stranger’s phone with Bluetooth off and Focus off | Step 2 settings; T-Mobile says to turn off Bluetooth because the ring may go to a paired device | You |
| Saved contacts ring, new numbers go to voicemail | Silence Unknown Callers, Call Screening, Pixel Call Screen, a Focus allow-list | Stranger Rule: one call from a saved contact, one from a number the phone has never seen | Set iPhone Call Screening to Never or Ask Reason for Calling; turn off Pixel automatic screening for first-time callers | You |
| Every call goes straight to voicemail; phone never rings | Unconditional forwarding left on | Have a stranger call: straight to voicemail with no ring points at forwarding; on iPhone, check Settings > Apps > Phone > Call Forwarding is off, then use the carrier’s code as well | Verizon *73; T-Mobile ##004# and ##21#; AT&T in the phone’s menu | You, then carrier |
| Callers hear a busy tone | Forwarding to a wrong or busy number | Call the forwarding destination directly | Re-enter the forward (Verizon *72 + 10 digits) or cancel it | You |
| Desk phone or softphone silent; mobile app rings | Device not registered to the VoIP platform | Check the line’s registration status on the phone or in the admin portal | Re-register: reboot, sign back in, check network | Your phone-system admin |
| Rings at some hours, not others | Business-hours rule, wrong time zone, after-hours flow to voicemail | Call at 8:55 am and 5:05 pm | Correct hours and time zone in the auto attendant | Your phone-system admin |
| Some team members ring, others never do | Ring-group or call-queue rules: not opted in, not on shift, presence not Available | Check each person’s opt-in and presence | Opt in, fix presence, check agent alert time | Your phone-system admin |
| Started the day you switched provider; some callers reach the old system | Port in progress, or old provider’s “residual translations” | Ask the new provider for port status and activation time | Keep the old service live until the port completes; ask the old provider to remove the numbers | Old and new provider |
| No calls at all, from anyone, on any device | Carrier outage, billing block, account not provisioned | Check the carrier’s outage page; call your own number from another network | Contact the carrier | Carrier |
| Specific callers never ring and nothing appears in Recents | Blocked number, carrier spam filter, area-code filter | Check Blocked Contacts and the carrier filter app’s blocked-call log | Unblock, add to allowed list, turn off area-code filters | You, then carrier |
Step 1: Is it every phone or just one device?
Have someone ring your number from a phone that has never called you while you watch every device that should ring. If a second device rings (a desk phone, a softphone, the mobile app), the fault is on the silent device: go to step 2. If nothing rings anywhere and the caller hears ringing, a recording, a busy tone or voicemail, the fault is upstream: go to step 3.
T-Mobile’s troubleshooting page (read through a text reader, because t-mobile.com refused our direct fetch) suggests the same split: call your own number to check whether it rings before voicemail, or move the SIM to another T-Mobile device and have someone call you. Apple suggests trying calls in another location, which separates coverage from settings. T-Mobile also names two device causes people miss. With Bluetooth on, “the device may be trying to send the ring to a paired device.” And a notification switch on the side of some phones can silence alerts from “anyone who is not a favorite contact.”
Step 2: Do Not Disturb, Focus and Silence Unknown Callers
iPhone. Apple’s article “If your call fails or you can’t receive calls on your iPhone” first suggests a carrier settings update, an iOS update and Reset Network Settings (which erases saved Wi-Fi passwords), then lists these checks: turn Airplane Mode on and off, waiting five seconds; check Do Not Disturb (Settings > Focus > Do Not Disturb); check Blocked Contacts and Call Forwarding (Settings > Apps > Phone); and check Silence Unknown Callers. With that on, Apple says “a caller must be listed in your Contacts or Recents,” or have shared their number in Mail or messaged you, “for their call to go through.” Apple adds that other Focus options “can also prevent you from receiving calls,” and that Do Not Disturb can run on a schedule (Settings > Focus > Do Not Disturb > Set a Schedule).
Apple’s iPhone User Guide also describes three choices for unknown numbers under Settings > Apps > Phone. Never: Call Screening is off and unsaved numbers ring. Ask Reason for Calling: unknown callers are asked for more information before the iPhone rings. Silence: unsaved numbers are silenced, sent to voicemail and shown in Recents. A separate Spam filter silences calls your carrier identifies as potential spam or fraud. For a business line, Never is the only choice under which a first-time caller rings straight through.
Android and Pixel. Google puts Do Not Disturb under Settings > Modes, where each mode’s Notification filters set who can interrupt, and notes that “settings can vary by phone.” The Phone app’s Blocked numbers setting Unknown blocks only private or unidentified numbers; Google says “you will still receive calls from phone numbers that are not stored in your contacts.” Pixel’s Call Screen can answer calls automatically (Phone app > Settings > Spam and Call Screen). Google lists the caller types screened as spam, possibly faked numbers and first-time callers, and says that if Call Assist decides a screened call is spam, “your phone hangs up.”
| Setting | Platform | What it does to a new customer’s call | Repeat-caller exception |
|---|---|---|---|
| Do Not Disturb / Focus | iPhone | Silenced unless the person or group is allowed | Optional: two or more calls from the same person within 3 minutes |
| Silence Unknown Callers / Call Screening: Silence | iPhone | Silenced, sent to voicemail, shown in Recents | Not a repeat rule: numbers in Contacts or Recents, or shared in Mail or Messages, ring |
| Call Screening: Ask Reason for Calling | iPhone | Asked for name and reason before the iPhone rings | Not applicable |
| Do Not Disturb (Modes) | Android | Blocked unless allowed under People | Optional: same person calls twice in 15 minutes |
| Call Screen, automatic | Pixel | Answered by Call Assist; rings only if not judged spam | Not applicable |
| Blocked numbers: Unknown | Phone by Google | Blocks private or unidentified numbers only | Not applicable |
The repeat-caller windows differ by a factor of five: Apple’s Focus lets through repeated calls within 3 minutes, Android’s Do Not Disturb a second call within 15 minutes. Neither helps a customer who tries once and rings the next business on the list.
Step 3: Call forwarding left on, or forwarding to the wrong place
If nothing rings anywhere, check whether your carrier is sending calls elsewhere. Verizon is blunt: “When Call Forwarding is turned on, your mobile phone won’t ring when you receive a call.”
- Verizon: *72 plus the 10-digit number forwards every call; *71 forwards when the phone is “busy or unanswered after 3-6 rings”; *73 turns forwarding off, with a confirmation tone that “may sound like a busy signal.” If callers get a busy tone after you set forwarding, Verizon says extra buttons may have been pressed; set it again with *72 and the full number.
- T-Mobile: when all incoming calls go to voicemail, T-Mobile says to dial ##004# to reset busy, unreachable and no-reply forwarding and ##21# to reset unconditional forwarding, which its short-codes page says “prevents calls to your number.”
- AT&T: “you can only change your call forwarding settings from your wireless phone,” not online, and forwarding “overrides your wireless voicemail.”
- iPhone: Apple says “the Call Forwarding icon appears in the status bar when call forwarding is on” (Settings > Apps > Phone > Call Forwarding). That menu has no busy or not-in-service option; Apple says to ask your carrier about conditional forwarding, so check those forwards with the carrier codes.
On VoIP, a forwarding loop (A forwards to B, which forwards back to A) does not ring forever. RFC 3261, the SIP standard, gives every request a Max-Forwards count that “SHOULD be 70”; it drops by one per hop, and at zero the request is rejected with a 483 Too Many Hops error response. The full code table for six carriers is in our guide to conditional call forwarding codes on iPhone and Android.
Line ringing again but still missing calls? Zian’s AI Receptionist answers inbound calls 24/7, books the appointment and follows up by SMS, WhatsApp or email when your team cannot pick up. Apply For Partnership
Step 4: Why does my VoIP desk phone or softphone not ring?
A desk phone or softphone rings only while it is registered with the platform. RFC 3261 puts it plainly: “Registrations are soft state and expire unless refreshed.” If the phone loses its network or a router drops the refresh, the registration lapses and the call has nowhere to go. When a proxy has no registered device left to try, it must return an error, which “SHOULD be the 480 (Temporarily Unavailable) response”; the standard’s examples of an unavailable callee include one who “is not logged in” or “has activated the ‘do not disturb’ feature.” A 480 in your call log is a reason to check that device’s registration and Do Not Disturb first. The 60-second test: compare the line status on the phone or softphone with the device list in your admin portal. Unregistered, offline or signed-out devices will not ring, even when the same user’s mobile app does.
Business-hours and time-zone rules. Platform defaults can silence a line. For a Teams auto attendant, Microsoft says that “if business hours aren’t changed, the Business-hours call flow is followed from 9:00 AM to 5:00 PM (09:00-17:00), and the After-hours call flow is followed outside of these hours, every day of the week,” in the time zone you select. As at 8 November 2026, Microsoft’s page carries a caution: Daylight Saving Time ended in North America on 1 November 2026, but Alberta, British Columbia and Manitoba stay on it, and auto attendants serving them need their time zone changed by hand. A wrong zone shifts every rule by an hour.
Ring groups and call queues. In a Teams call queue, “only representatives who are on shift, opted in, and are available (if Presence-based routing applies) receive calls.” Microsoft recommends letting agents opt out, which means an agent can opt out and forget, and an agent alert time of at least 20 seconds before the queue moves to the next person. Ring groups and hunt groups on other platforms raise the same questions: is the person included, is the rule active now, and does their status receive calls? If your number lives in HighLevel, our guide to missed call text back in HighLevel shows where its Incoming Call Timeout and call-status filters are set.
Step 5: Is a number port in progress?
If the problem started when you changed provider, suspect the port. Under 47 CFR 52.35, carriers must complete a simple wireline-to-wireline or simple intermodal port “within one business day unless a longer period is requested by the new provider or by the customer.” Business days are Monday to Friday, with business hours of at least 8 am to 5 pm, excluding the current provider’s holidays. A complete request received between 8 am and 1 pm local time can be activated at midnight that day; a later one counts as received at 8 am the next business day, so one arriving at 1:05 pm on a Friday counts as received on Monday. Non-simple ports, and carriers with an FCC waiver, have four business days. “Intermodal” here covers wireline-to-wireless, wireless-to-wireline and ports involving interconnected VoIP; the section sets no interval for wireless-to-wireless ports.
The common self-inflicted gap is cancelling the old service early. Amazon’s Connect documentation says that “releases your phone number assignment, and might result in you losing the number.” Zoom’s porting FAQ says existing service “will work as is during the porting process if you do not make any account changes.” Zoom also names a fault that looks exactly like a phone not ringing: after a completed port, calls can still route to the old system because of “Residual Translations,” which the old provider has 24 hours to remove and should be asked to clear. The same page warns that “Expedited porting isn’t possible” and that reversals “aren’t universally supported.”
Step 6: Is it a carrier outage?
If no device rings and no setting explains it, go to the carrier. Apple says to confirm with your carrier that your account is set up for the phone, that there are no localised outages, no billing-related block and no errors on the carrier system. T-Mobile’s list starts with an active line (prepaid lines need a balance), at least two signal bars, and Family Allowances not blocking calls by time of day. AT&T’s outage page asks you to sign in or enter an account phone number to see outages for your address. Then split by network: ring your number from a mobile on another carrier, and from a landline or VoIP number. If one network fails and others ring, tell your carrier which. Bring evidence: the time of each failed test call, the calling number, what the caller heard and which devices rang.
Step 7: Call blocking and spam-filter apps
A block leaves the fewest traces. Google says calls from a number “while it was blocked won’t show in your call history.” On iPhone, check Blocked Contacts and the Unknown Callers and Spam lists in the Phone app.
Carrier filters are the bigger risk for a local business. Verizon says Call Filter “blocks high-risk spam calls by forwarding to voicemail,” and its Neighborhood Filter can forward calls from your own area code and prefix to voicemail. For a business whose customers live nearby, that filters its own customers, and Verizon says it “may inadvertently block some legitimate calls.” Deleting the Verizon Protect app “doesn’t turn off spam filtering”; you must turn the filter off or unsubscribe. On iOS 14 and later, Verizon’s Silence Junk Callers is auto-enabled, and Verizon notes “wanted calls may be inadvertently blocked.” Add regular callers to your contacts or the app’s allowed list.
Under 47 CFR 64.1200(k)(3), a terminating carrier may block on reasonable analytics without liability where several conditions are met, one being that “a consumer may opt out of blocking and is provided with sufficient information to make an informed decision.” Under (k)(11) it may also block calls it determines are highly likely to be illegal without offering an opt-out, provided it discloses that it engages in such blocking. Under (k)(10), a carrier that blocks under an opt-out or opt-in analytics program must, at the request of the subscriber to a number and at no additional charge, provide within 3 business days a list of calls to that number it blocked in the previous 28 days, with the date, time and calling number. Ask for that list when the blocked-call logs on your phone and in the filter app show nothing. Under (k)(8), a carrier that blocks under the section, or uses caller ID authentication information to decide how to deliver calls, must publish a single point of contact for blocking-error complaints. That route belongs to the caller, and when it finds a number was wrongly blocked it must promptly stop that treatment unless circumstances change. For caller ID authentication disputes it must “at a minimum, provide a status update within 24 hours.” If your own outbound calls are being labelled rather than blocked, see our guide to Scam Likely labels and who to contact.
What does a phone that does not ring cost? A worked example
Take one quiet failure from step 4: an auto attendant left on Microsoft Teams’ default 09:00–17:00 at a business that answers 08:00–18:00, Monday to Friday. The default is the sourced figure; every rate is an illustrative assumption to replace with your own call log.
| Input | Value | Source |
|---|---|---|
| Hours a day sent to the after-hours flow while staff are working (08:00–09:00 and 17:00–18:00) | 2 hours | Microsoft default 09:00–17:00 vs your real hours |
| Weekdays affected | 5 | Your hours |
| Calls per affected hour | 2 | Illustrative; read your log |
| Share that are new enquiries | 40% | Illustrative |
| Share of answered new enquiries that book | 30% | Illustrative |
| Share who would have rung back anyway | 30% | Illustrative |
| Gross profit per booked job | US$200 | Illustrative; job value × margin |
2 hours × 5 days × 2 calls = 20 calls a week sent to the after-hours flow. 20 × 40% = 8 new enquiries; 8 × 30% = 2.4 bookings; 2.4 × (1 − 30%) = 1.68 bookings genuinely lost; 1.68 × US$200 = US$336 of gross profit a week, from two misconfigured hours a day. Because the default applies every day of the week, weekend calls from 09:00 to 17:00 also ring staff who are not there, a second cost this example leaves out. The same formula, extended to text-back recovery and its costs, is in our missed call text back ROI calculator.
Frequently asked questions
Why does my phone go straight to voicemail without ringing?
The usual causes are unconditional call forwarding left on, Do Not Disturb or a Focus, or Silence Unknown Callers. On Verizon, *73 turns forwarding off. On T-Mobile, ##004# and ##21# reset it. On iPhone, Apple’s support article on calls that will not come through lists Do Not Disturb, Blocked Contacts, Call Forwarding and Silence Unknown Callers as the settings to check.
Why do some callers get through but new customers don’t?
Settings that filter unknown numbers let saved contacts ring and silence everyone else. Check iPhone’s Silence Unknown Callers and Call Screening, Pixel’s automatic Call Screen for first-time callers, and any Focus that allows only certain people. Always test from a number your phone has never seen.
Can my carrier block calls to my business without telling me?
Yes, within limits. Under 47 CFR 64.1200(k), a carrier may block on reasonable analytics if you can opt out, and may block calls it judges highly likely to be illegal without an opt-out if it discloses that it does so. A carrier blocking under an opt-out or opt-in analytics program must, on your request and at no extra charge, give you within 3 business days a list of calls to your number it blocked in the previous 28 days. Verizon’s Call Filter sends high-risk spam to voicemail, and its Neighborhood Filter can send calls from your own area code to voicemail. Check the filter app’s blocked-call log.
How long can a number port stop my phone ringing?
The FCC’s rule at 47 CFR 52.35 requires a simple wireline-to-wireline or simple intermodal port within one business day (four for a carrier with an FCC waiver), and a non-simple port within four business days, unless a longer period is requested. It sets no interval for wireless-to-wireless ports. Keep the old service active until the port is confirmed working.
Why does my VoIP desk phone not ring when my mobile app does?
The desk phone has probably lost its registration with the platform. Under RFC 3261, registrations expire unless the device refreshes them, and an unregistered device has nowhere for the call to be delivered. Check the line status on the phone, then reboot it or sign it back in.
Will an AI receptionist fix a phone that does not ring?
Only if the calls reach your number. An AI receptionist answers calls your carrier forwards to it when you do not answer, are busy or are unreachable. It cannot answer a call lost to an outage, a port in progress or a carrier block, so run the seven checks first.
Where every figure on this page comes from
| Figure | Who published it | Link | Date read |
|---|---|---|---|
| Airplane Mode: wait five seconds; settings checked in order; carrier checks (outages, billing block); diagnostics on iOS 18 and later | Apple | support.apple.com/en-us/118427 | 8 November 2026 |
| Focus repeated calls: two or more calls within 3 minutes | Apple | iPhone User Guide: Focus notifications | 8 November 2026 |
| Call Screening options Never / Ask Reason for Calling / Silence | Apple | iPhone User Guide: Screen and block calls | 8 November 2026 |
| Other Focus options can prevent calls; Do Not Disturb schedules | Apple | support.apple.com/en-us/105112 | 8 November 2026 |
| Android repeat callers: twice in 15 minutes | Android Help: Modes and Do Not Disturb | 8 November 2026 | |
| Blocked numbers “Unknown” scope; blocked calls not in call history | Phone app Help: Block or unblock | 8 November 2026 | |
| Pixel Call Screen: spam calls hung up; screened caller types on Pixel 7 and later | Pixel Phone Help: Call Screen | 8 November 2026 | |
| ##004#, ##21#; Bluetooth; at least two signal bars; error messages for Customer Care | T-Mobile (read via r.jina.ai text reader; direct fetch refused) | T-Mobile: can’t call and other calling issues | 8 November 2026 |
| Unconditional forwarding “prevents calls to your number” | T-Mobile (read via r.jina.ai text reader) | T-Mobile: self-service and short codes | 8 November 2026 |
| *72, *71, *73; “3-6 rings”; 10-digit number | Verizon | Verizon Call Forwarding FAQs; Turn Call Forwarding On | 8 November 2026 |
| Forwarding changed only from the phone; busy destination gives a busy signal | AT&T | AT&T Call Forwarding for Wireless | 8 November 2026 |
| Outage details require sign-in or account phone number | AT&T | AT&T outages | 8 November 2026 |
| Max-Forwards 70; 483 Too Many Hops; registrations expire unless refreshed; 480 Temporarily Unavailable | IETF (RFC 3261) | RFC 3261 | 8 November 2026 |
| Default business hours 09:00–17:00 every day; DST ended 1 November 2026; Alberta, British Columbia, Manitoba | Microsoft | Microsoft Learn: Auto attendant setup | 8 November 2026 |
| Agent alert time at least 20 seconds; on shift, opted in, available | Microsoft | Microsoft Learn: Call queue setup | 8 November 2026 |
| One business day; 8 am–1 pm request window; four business days (non-simple ports and waiver carriers); 8 am–5 pm business hours | FCC (eCFR, 47 CFR 52.35) | 47 CFR 52.35 | 8 November 2026 |
| Opt-out of analytics blocking; blocking without opt-out for calls highly likely to be illegal ((k)(11)); blocked-call list within 3 business days covering 28 days ((k)(10)); status update within 24 hours (caller ID authentication disputes) | FCC (eCFR, 47 CFR 64.1200) | 47 CFR 64.1200 | 8 November 2026 |
| Residual translations: old provider has 24 hours | Zoom | Zoom porting troubleshooting and FAQ | 8 November 2026 |
| Cancelling before the port may lose the number | Amazon Web Services | Amazon Connect admin guide | 8 November 2026 |
| Call Filter to voicemail; Neighborhood Filter; Silence Junk Callers on iOS 14 and later | Verizon | Verizon Call Filter FAQs | 8 November 2026 |
| 50,769+ qualified sales appointments; 30+ languages; 24/7 | Zian AI (first-party) | zian.ai | 8 November 2026 |
| Worked-example rates (2 calls an hour, 40%, 30%, 30%, US$200) | Illustrative assumptions by this page | Not applicable | Not applicable |
When the line rings and nobody can take it. Zian’s AI Receptionist answers inbound calls 24/7, qualifies and books callers, transfers to your team and follows up across voice, SMS, email, WhatsApp, Instagram DMs and Facebook Messenger. Zian is in a partnership-application beta. Apply For Partnership