Subject: CRITICAL BUG - SIP re-INVITE rejected (486) Impact: All call queue/hunt group transfers fail Description: When NetSapiens sends a mid-call re-INVITE to update the media path (standard SIP behavior when an agent answers), Retell AI responds with 486 Rejected instead of accepting the SDP update. This makes Retell AI incompatible with ANY call queue system that uses re-INVITE for media path updates. RFC 3261 Section 14: re-INVITE is standard for session modification. Rejecting it breaks call queues, consultative transfers, and hold/resume. Workaround attempts: - Tried blind transfer via Forward Always (still triggers re-INVITE) - Tried auto-attendant relay (still triggers re-INVITE) - NetSapiens doesn't send REFER to external parties on internal forwards Request: Fix re-INVITE handling to accept SDP updates per RFC 3261. Attached: SIP trace showing 486 rejection of re-INVITE. See line 193 https://cdn.discordapp.com/attachments/1471678418109333584/1471678418226516050/5cc8dbca88e6ddd652a9b5167cb87ad0.csv?ex=698fced5&is=698e7d55&hm=71e07d20311fcff3cc720f39cce303929a992b60d80d98a8313eec6d40382275&

Hi @Mark

I believe this is the matching call: call_709a10d8f400c95023e4f7a7c1b

Hello @Mark , re invites is not supported YET.

Any timeline for availability? I will need to use a different platform if it's going to be a while.

I don't have an exact timeline on it, but its in the plan any update on it I will let you know.