VoIP.info Troubleshooting

Inbound VoIP calls do not reach the business

Trace carrier delivery, Asterisk endpoint identification, DID matching and the final destination without collapsing the boundaries.

Reviewed 2026-10-19First-party Asterisk documentation and SIP standard reviewed September 30, 2026; FreePBX 17 terminology retained; no PBX, provider, number, route or live call testIntermediateDocumentation based · not lab tested

Find the last successful boundary

Call the published number from an independent outside service. Record the source, destination, exact time, caller experience and carrier call identifier. At the PBX edge, capture whether an INVITE arrived and retain its Call-ID, source address, Request-URI and To header. Protect the trace because signaling can contain identities, dialed numbers and credentials.

If no request reaches the managed edge, move upstream through number assignment, provider route, provider trace and firewall or SBC admission. Do not change the PBX dialplan to compensate for an INVITE that was never delivered.

Inbound and outbound routing are separate
Inbound calls use called-number matching to reach an extension, queue or IVR. Outbound calls use dialed-number rules to choose a permitted trunk.

A working outbound call does not prove inbound number routing. Diagnose the direction and the matching rule independently.

Prove which endpoint Asterisk selected

Every inbound SIP request must be associated with an Asterisk endpoint before it can enter that endpoint's context. Use the live logger and pjsip show endpoint evidence to confirm the selected endpoint, loaded Identify object and expected source match. Asterisk can identify by the From user or by an IP Identify object depending on loaded modules and configuration.

Do not interpret every 401 response as a bad password: Asterisk documents a dummy challenge when it cannot identify an endpoint. Prove endpoint recognition first, then examine any real authentication exchange. Avoid enabling an anonymous endpoint as a shortcut unless anonymous admission is an intentional, restricted design.

Follow the delivered number into the running dialplan

Record the number format actually delivered in the Request-URI and compare it with the endpoint context and inbound-route match. Country code, leading plus, national prefix and provider-added digits can select a different extension. Caller-ID screening is a separate decision from the called number.

Asterisk's rejection notice names the selected endpoint, requested extension and context when no extension exists. Use dialplan show <context> to inspect the running dialplan. In FreePBX, verify the intended route and destination were saved and applied; generated dialplan is runtime evidence, not the durable edit surface.

Follow the destination

After a route matches, follow time conditions, manual overrides, ring-group membership, queue admission, extension dialing and voicemail fallback. A correct DID match can still lead to an unavailable extension or an after-hours destination the caller did not expect. Keep a dial attempt, provisional response, answered bridge and usable media as separate outcomes.

Retest narrowly

Test the repaired number from an outside service, then test another existing number to detect an overly broad match. Confirm the expected daytime or after-hours destination without leaving a catch-all route in place merely because it masks an unexplained mismatch. Keep the carrier and SIP identifiers with the incident if upstream escalation is required.

When more than the intended PBX rings

Use the A&A target-graph diagnostic when one inbound call alerts an old device and the PBX. It resolves provider-side branches before changing the PBX route.

Separate Zen inbound signaling from the later audio path

If a Zen call reaches and answers on the PBX but audio is missing, continue with the Zen media diagnostic rather than changing inbound routing that already completed.

When a SureVoIP alternate destination never receives an attempt

The SureVoIP destination diagnostic follows one number from the configured route order through the first outcome, timeout trigger, next attempt and recovery.

Keep caller-name lookup after carrier delivery and route matching

If an inbound call reaches FreePBX but displays the wrong name, follow the CallerID Lookup diagnostic from the matched route through the source, cache and destination channel.

When Magrathea does not send a call to one nominated IP

Follow the Magrathea SIP Resilience workflow from the selected number and address pool through health probes, distribution, INVITE arrival and PBX route.

When an NFON backup PBX receives no inbound calls

Follow one number through NFON trunk-set membership, endpoint selection and PBX routing before changing registration or firewall state.

Trace SIPTRUNK delivery from the selected authentication mode

For registered service, SIPTRUNK uses the REGISTER Contact for inbound delivery; for IP authentication it uses the stored public address and port. The mode-mismatch diagnostic follows that destination through DID assignment, INVITE, number format and the first PBX route.

Trace Blink Reject or Busy before changing inbound routing

When one Blink user action stops parallel phones or voicemail, use the Blink inbound-disposition diagnostic to preserve the 603, 486 or absent response, identify which proxy cancelled branches and compare the final caller treatment.

Trace SIP.US inbound delivery beyond the working primary gateway

The SIP.US failover diagnostic follows current gateway acceptance, registered Contact or stored IP, DID primary and secondary trunk assignment, eleven-digit called number and first PBX rule before any fallback change.

Prove a Flowroute failover assignment before changing the PBX

The Flowroute inbound-failover diagnostic follows the number's primary and failover relationship IDs, destination types, first provider attempt, Request-URI and first PBX rule.

Prove DIDWW group policy before changing an inbound route

The DIDWW trunk-group diagnostic follows one DID through assignment, group membership, policy, first result, every later CDR and PBX handling.

Trace SIPStation delivery before changing a general inbound route

Use the SIPStation inbound diagnostic to prove account mode, registration address, provider fallback, first PBX request and DID match.

Trace an IP Telecom port and inbound target independently

For an IP Telecom number, use the provider record to preserve the accepted port state, delivered Request-URI and identity, first PBX match and final destination without assuming a general portability statement proves live routing.

Trace Clearfly inbound delivery through every routing layer

Use the Clearfly service record to preserve the public number, port state, delivered Request-URI and identity, PBX match, forwarding or attendant control and final destination without assuming a portal label proves delivery.

Trace Redcentric inbound delivery after number migration

Use the Redcentric service record to preserve port state, provider route, delivered Request-URI and identity, PBX match, call-flow object, destination, answer and media without treating project completion as delivery proof.

Verify that CommPeak DID service is actually in scope

CommPeak lists DIDs separately from SIP termination. Use the provider record to prove number ownership, provider route, delivered Request-URI and identity, PBX match, destination, answer and media before changing the trunk.

Trace Voximplant ingress beyond the IP allowlist

Use the Voximplant provider record to compare source address, Request-URI, identity, application-rule match, scenario event, next leg, destination answer and media before changing the trunk.

Trace TelVox SIP delivery and webhook execution separately

For TelVox Connect, use the provider record to correlate trunk state, SIP dialog, voice-webhook request, five-second application response, returned markup, later callback and media outcome without treating any one layer as end-to-end proof.

Do not let VoIP Much registration stand in for number routing

For VoIP Much, prove the owned number, provider route, delivered identity, selected PBX rule and destination separately with the provider-specific diagnostic.

Prove the VoIPline number route after registration

The VoIPline diagnostic separates an active or ported number, provider route, delivered identity, PBX rule and final destination.

Trace one Voip Unlimited DDI from alias to destination

The Voip Unlimited diagnostic proves provider assignment and delivery before changing a general inbound route.

Prove the SignalWire resource assignment before widening a route

The SignalWire diagnostic distinguishes a phone number assigned to a SIP endpoint from a Resource SIP Address and then traces the PBX context and DID.

Prove Telnyx number assignment, region and first attempt

The Telnyx inbound-route diagnostic compares the number-to-Connection relationship, selected inbound region, current network evidence, delivered request and first PBX match.

Prove the Bandwidth number, routes and first attempt

The Bandwidth inbound-route diagnostic compares number voice mode, effective routes, weighted endpoints, actual attempts and the first PBX match.

Prove the Voipfone portal route before changing the PBX

The Voipfone inbound-number diagnostic starts with the number’s effective destination, then follows provider attempt, delivered identity and PBX match.

Prove the VoIP.ms DID route and POP before changing the PBX

The VoIP.ms DID diagnostic starts with the number’s effective route and POP, then follows provider attempt and PBX match.

Prove Twilio URL selection before changing the inbound route

The Twilio origination diagnostic begins with the number, Trunk SID and effective OriginationUrl resources before the PBX match.

Prove the Plivo number-to-URI chain before changing routing

The Plivo inbound diagnostic starts with number assignment and the effective primary and fallback URI before the PBX match.

Prove the Vonage number-to-URI chain first

The Vonage inbound diagnostic starts with the number link and effective priority and timeout before the PBX match.

Start a Voxtelesys inbound incident at the DID route profile

The Voxtelesys diagnostic proves number assignment and effective destinations before changing registration, firewall or PBX routing.

Start Amazon Chime inbound incidents at number assignment

The Amazon Chime diagnostic proves the assigned connector or group before changing origination routes, firewall or PBX routing.

Begin a didlogic inbound incident at the purchased number

The didlogic diagnostic proves the destination type and target before changing registration, firewall or PBX routing.

Check Callcentric DID Forward before the PBX path

Callcentric direct DID Forward rules outrank Call Treatments. The diagnostic establishes whether an INVITE should have reached the customer edge at all.

Trace an Anveo Direct DID to its exact SIP URI

A working outbound trunk and an absent REGISTER status do not explain inbound routing. Use the Anveo Direct diagnostic to follow the DID, primary URI, provider attempt and PBX match.

Follow a CarrierX DID through its assigned group

Use the CarrierX trunk-group diagnostic to distinguish number assignment, provider selection, edge receipt, PBX matching and media.

Follow an AVOXI number through its enabled rule

Use the AVOXI SIP URI diagnostic to distinguish number mapping, URI configuration, provider attempt, PBX matching and media.

Do not let an Easybell registration hide the inbound mode

Use the Easybell diagnostic to distinguish credential registration, IP-only delivery, FQDN targeting, PBX matching and Offline forwarding.

Check SIP.US Forward and Backup before rewriting routes

A DID can intentionally bypass the PBX through PSTN Forward, while Backup has a narrower trigger. Use the SIP.US diagnostic to preserve precedence and capacity evidence.

A correct Flowroute route can still have a separate media failure

First prove number relationship and provider edge, then use the Flowroute audio diagnostic if signaling completes without sound.

A Bulk Solutions outbound success does not establish inbound DID assignment

Use the Bulk Solutions diagnostic to trace trunk-group ownership, edge receipt, Request-URI and route matching.

A Yay.com trunk can exist while its number routes elsewhere

Use the Yay.com diagnostic to prove number assignment, delivered identity, destination and first PBX route.

A ClearlyIP DID can select another Location or identity

Use the ClearlyIP diagnostic to prove Primary or Smart Routing ownership and the delivered number form.

A working Simwood outbound call does not prove inbound registration

Use the Simwood diagnostic to prove the provider binding and attempt before PBX route changes.

A working Sinch termination leg does not prove origination

Use the Sinch diagnostic to prove the number's origination application and actual customer-facing attempt.

A registered SIPTRUNK Contact can still point to the wrong destination

The SIPTRUNK diagnostic compares Contact, provider source, attempt and first PBX response.

Watch the explanation

Grandstream GRP phones: prevent accidental DND activationVoIP knowledge · Version-specific

Learn the difference between turning Do Not Disturb off and removing the user controls that enable it. The demonstration examines the idle mute-key action and the separate DND feature setting, which can matter when users accidentally stop their phones ringing.

Read applicability and editorial notes →
Watch this video here

GRP-family web interface; the spoken model number is unclear. Match the controls to your exact model and firmware before applying a policy change. Review used the available transcript and primary references; audio and screen readability remain unverified.

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Sources & applicability

Primary references for the technical details above. Operational examples and planning checklists are VoIP.info editorial guidance.

Examples require adaptation to your topology. No live PBX or hardware testing is claimed.