Quick troubleshooting view
The destination rejects the media offer or selected SDP parameters.
- No common codec
- SRTP required or forbidden
- Incompatible DTMF mode
- Capture the INVITE and 488 response
- Compare codecs
- Check SRTP/RTP requirements
- Correct only the component confirmed by the checks
- Retest the original symptom after the change
- Escalate with collected evidence when the cause remains unclear
Contextual technician plan
Perform this check and preserve the observed result before changing configuration.
“Capture the INVITE and 488 response” should produce an observation that clearly confirms or rules out “No common codec”.
If the observation is normal, lower “No common codec” in the ranking and continue with the next distinct check.
If the observation is abnormal, keep the evidence and investigate “No common codec” first. Related action: Correct only the component confirmed by the checks.
Perform this check and preserve the observed result before changing configuration.
“Compare codecs” should produce an observation that clearly confirms or rules out “SRTP required or forbidden”.
If the observation is normal, lower “SRTP required or forbidden” in the ranking and continue with the next distinct check.
If the observation is abnormal, keep the evidence and investigate “SRTP required or forbidden” first. Related action: Retest the original symptom after the change.
Perform this check and preserve the observed result before changing configuration.
RTP should be visible in both directions with source/destination IP addresses and UDP ports consistent with SDP and the expected NAT path.
Bidirectional RTP is present; investigate codec negotiation, endpoint audio or media processing rather than basic NAT reachability.
Missing RTP in one direction points to NAT/firewall
Repeat the same validation test after the correction and confirm the original symptom is gone. Validate stability before closing the incident.
Before changing configuration, record the current value and a way back.
Escalate with the exact symptom, scope, timestamp and completed checks when the issue remains unresolved.
＋Open the complete detailed guideDetailed explanations and original troubleshooting content.
The destination rejects the media offer or selected SDP parameters.
Likely causes
- No common codec
- SRTP required or forbidden
- Incompatible DTMF mode
- SDP rewritten by SBC/NAT
Checks in priority order
- Capture the INVITE and 488 response
- Compare codecs
- Check SRTP/RTP requirements
- Retry with a minimal media offer
When to escalate
Escalate when the failure affects multiple users, a production dependency is unavailable, or logs show a component outside your control. Include timestamps, scope, tests already performed, and the last known working state.