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SignalWire SIP credential registers but calls fail

Follow one failed inbound or outbound call through the SIP Profile, credential handler, number assignment, PBX context or route, caller identity, encryption, SDP, media and provider log.

Reviewed 2026-10-17Current SignalWire SIP trunking, SIP Credential, SIP Profile, FreePBX, caller identity, rate-limit and E911 documentation reviewed October 17, 2026. The documentation distinguishes a project SIP Profile, one SIP Credential, a number-to-resource assignment, Resource SIP Addresses, the credential call handler, permitted outbound identity, PBX registration and dialplan, negotiated signaling and media, account-level call-start limits and number-level E911 provisioning. The selected Space, project, profile revision, credential, password, handler, phone number, assigned resource, PBX object, route, caller identity, encryption, codec, cipher, call rate, concurrency, emergency record, availability, price and compatibility remain account, configuration or observation specific. No account, project, credential, profile, number, resource, PBX, registration, packet, media stream, emergency workflow or live call was inspected or testedAdvancedDocumentation based · not lab tested

Freeze one direction, one call and every object identity

Record whether the symptom is inbound PSTN, inbound SIP-address, outbound PSTN or outbound resource handling. Preserve the Space and project, SIP Profile domain and revision, credential resource ID and username, effective call handler, phone number and assigned resource, Resource SIP Address when used, PBX endpoint, context or route, timestamp and timezone, provider log, first packet, SIP result, SDP, media and caller outcome. Redact passwords, API tokens, Authorization headers, personal numbers and packet payloads.

Classify the first missing boundary: registration, number assignment, resource address, inbound provider attempt, PBX edge receipt, endpoint match, DID extraction, route selection, handler authorization, caller identity, provider acceptance, encryption negotiation, media or answer. A registered credential does not select the rest of this chain.

Reconcile profile defaults, credential values and the loaded registration

Compare the project SIP Profile with the selected credential's domain, handler, send_as, encryption, codec and cipher values, then compare both with the loaded PBX object and observed REGISTER. Preserve the challenge, Contact, expiry, transport, response and the current public source. Confirm that a production PBX—not a retired phone, lab host or stale NAT mapping—owns the binding.

If the registration is current, stop rotating credentials. A profile update does not rewrite an individual credential or PBX, and registration success does not prove that the credential inherited the handler or security policy the operator expected.

For inbound failure, prove the assigned resource before the PBX route

For a purchased number, inspect the number's current Voice and Fax handling and exact assigned SIP endpoint resource. For direct inbound SIP, inspect the Resource SIP Address and its owning resource. Correlate the SignalWire log with the edge packet, Request-URI, To header and response.

If the call reaches the documented FreePBX path, preserve the from-signalwire context, custom number extraction, normalized DID, first from-pstn route and destination. Correct an absent or wrong resource assignment before changing FreePBX. Correct a demonstrated context or normalization error before adding a catch-all route.

For outbound failure, prove handler, route and Send As identity

Determine whether the credential uses profile-default, passthrough, block-PSTN or resource handling. Preserve the dialed form, PBX outbound route, first INVITE, From and asserted identity, endpoint or profile send_as, purchased or verified number, SignalWire response and downstream result. Keep API management credentials out of the SIP-authentication investigation.

A blocked handler, wrong resource target, rejected originating number and destination failure require different corrections. CNAM approval or display is downstream identity evidence and does not prove that the numeric caller ID was authorized or accepted for the call.

Keep call-start limits, encryption and media outside route selection

Correlate the account-level Voice call-start limit and backlog with the call timestamp, but do not label a one-call failure as throttling without provider evidence. Keep call-start throughput separate from simultaneous connected calls and PBX channel limits.

If signaling succeeds, compare effective encryption policy, transport, certificate result, SDP, selected codec and cipher, RTP endpoints and both media directions. Do not change number assignment or dialplan to repair a certificate, SRTP, codec, NAT or RTP-path failure. A call log row and packet counters are not audible two-way-media proof.

Correct the earliest proven mismatch and retest without emergency risk

Change only the demonstrated owner: profile default, credential value or handler, number assignment, Resource SIP Address, PBX registration, inbound context, DID extraction, route, originating identity, encryption policy, codec or network path. Preserve the old state and repeat one authorized non-emergency call in the same direction, recording provider log, SIP result, route, answer, two-way media and clean release independently.

For E911, wait for the number-level status to become active and use the provider-documented 933 read-back procedure; do not use a failed ordinary call as emergency-readiness evidence or place an uncoordinated 911 test. No account, credential, profile, number, PBX, packet, media stream, emergency workflow or live call was inspected or tested for this diagnostic.

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.

Continue your research

Provider research · Current SignalWire SIP trunking, SIP Credential, SIP Profile, FreePBX, caller identity, rate-limit and E911 documentation reviewed October 17, 2026. The documentation distinguishes a project SIP Profile, one SIP Credential, a number-to-resource assignment, Resource SIP Addresses, the credential call handler, permitted outbound identity, PBX registration and dialplan, negotiated signaling and media, account-level call-start limits and number-level E911 provisioning. The selected Space, project, profile revision, credential, password, handler, phone number, assigned resource, PBX object, route, caller identity, encryption, codec, cipher, call rate, concurrency, emergency record, availability, price and compatibility remain account, configuration or observation specific. No account, project, credential, profile, number, resource, PBX, registration, packet, media stream, emergency workflow or live call was inspected or tested

SignalWire SIP trunking: credentials, resources and call-path evidence

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