When calling in to Microsoft Teams the Teams client does not ring. The user has the dial pad and can make outbound calls.
In the portal the following error is displayed
Failure Advice: 404 Unallocated Number
2021-05-07 14:57:01 (UTC) SIP processing error Invalid argument 404 2021-05-07 14:57:01 (UTC) Reason header: Q.850 ;cause=1 ;text="3e5815f1-6343-4602-b941-3653b352e2ba;RNL" 2021-05-07 14:57:01 (UTC), new state => Closing Error, accepted => Y 404 Not Found
- log in to the Office 365 admin portal at https://www.office.com/
- Go to the Admin icon
- On the left hand side menu bar select "Show All" and the Support option will show,
- Create a support request entitled something like "Unable to receive calls in Teams (404 error)"
Within the detail of the support request, provide the following details:
- A User email address for one of the users with dial-pad that cannot receive calls
- Direct Routing is being used in Carrier Mode (SBCs will not show in the Teams Admin center)
- Enterprise Voice is enabled for the user
- The Voice Routing Policy is applied to the user
- The User has a valid Phone System licence
- The user can place outbound calls
- The correct number is showing on the Teams admin center and the user’s dial pad
- Microsoft Approved Direct Routing SBCs are being used.
- The calling service/trunk is getting a 404-rejection error from Microsoft Direct Routing when sending the call to Teams with messages such as "Reason header: Q.850 ;cause=1 ;text="4c5ea470-5ff3-4489-a9bc-7207c168c5f7;RNL" <- (insert a relevant code here)