SIP 403 Forbidden
AsteriskRFC 3261 §21.4.4The server understood the request but refuses to authorize it. Often caused by IP ACLs, blocked numbers, or trunk billing checks.
Common causes on Asterisk
- Trunk source IP not in allow-list
- Caller ID stripped, blocked, or not provisioned
- Outbound dial plan rejected the destination
- Account out of credit / suspended
Asterisk-specific note
Asterisk PJSIP returns 403 from `endpoint_identifier_anonymous` when no endpoint matches the source IP and anonymous calls are disabled. Check `pjsip show identifies`.
Stop guessing — paste your trace
Drop your PCAP or sngrep log and SIP Flow will render the ladder, surface the failing transaction, and (optionally) ask Gemini to suggest the fix grounded in Asterisk docs.
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