606
SIP
606 Not Acceptable
The user's agent was contacted successfully but some aspects of the session description (SDP) are not acceptable. Unlike 488, this is a global failure — no other server can satisfy this request.
이 코드를 보게 되는 경우
When the callee definitively cannot accept any of the offered media types or codecs. Different from 488 which is location-specific.
해결 방법
Check the Warning header or response body for which session parameters are unacceptable. Modify the SDP offer to use compatible codecs and media types.