"488 Not Acceptable Here" when joining Zoom meeting via SIP URI using Twilio

API and Webhooks
1

Hi Zoom Team,

We are trying to join a Zoom meeting using the SIP URI provided in the meeting invite through Twilio. However, Zoom consistently responds with 488 Not Acceptable Here.

We worked with Twilio Support, who reviewed the PCAP and confirmed that our SIP offer is compliant with Zoom’s requirements:

  • TLS signaling (transport=tls)
  • SRTP (RTP/SAVP)
  • AES_CM_128_HMAC_SHA1_80 crypto suite

According to Twilio, the 488 response from Zoom’s Room Connector Controller indicates the rejection is likely due to the Zoom meeting configuration or account entitlements, rather than a media or encryption mismatch.

Could you please help us identify the reason for the 488 response and advise what needs to be configured or enabled on the Zoom side for SIP URI dialing to work?

Thank you.