Overview

Calls to MS Teams numbers made from a particular third-party SIP device fail. The call rings for an MS Teams user but fails after the user attempts to answer the call.

Solution

Please note that one of the known root causes of such behavior is the device offering video codec in the invite, which is not supported by SBC. Check that no video is set up on the device profile (if needed, verify with Microsoft that video codecs are not offered from this particular device).

If you are sure that video is not offered, but the issue persists, to start with troubleshooting, we will need fresh call samples. Reproduce the issue and open a ticket with Support, making sure to describe the issue and any symptoms you observe, and add at least two call samples in the following format:

• Calling From Number:
• Calling To Number:
• Date of call: dd/mm/yy
• Time of call: xx:xx am/pm (time zone)
• Trouble observed: Inbound or Outbound
• Description of the failing scenario

Based on the troubleshooting, the Support team will either take action to fix the issue on our side or reach back with findings and any next steps required from you.

Verification

Once the root cause is fixed, try to replicate the issue to confirm that it is no longer there.