Unsupported Incoming issue with 3cx V20 and teams phone with SIP

[a.almualla]

Hi
We are experiencing an issue where calls to local extensions are immediately routed to voicemail without ringing the physical phones (e.g., Yealink MP54) that are provisioned with a custom template. When these extensions are not associated with physical phones, calls are correctly routed to Teams, and there are no issues. However, when the Yealink MP54 phones are added, the calls fail to ring and are sent directly to voicemail.

Steps followed for troubleshooting:
1- Enabled and Disabled voice mail on 3cx and on Teams "No effect"
2- tried enabling and disabling call forwarding using custom template "no effect"
3- If the phones are provisioned without SIP, it works perfectly!
4- Tried Loopback truck for those exts. 9XX and 2XX but with no luck.
5- The server is V20 with 500GB, 8 Cores, 16GB, so there is no over utilization of the Voicemail, and we also cleared Voice storage with no vail
6- It was working when we were on 3CX V18.9, this only happened after the upgrade to V20

more deta

 

[a.almualla]

If anyone is experiencing a similar issue, here's how we resolved it:

We use Yealink MP54 devices with Direct Routing and Microsoft Teams integrated via a custom template. Both the SIP client and Teams would ring simultaneously for the same extension, which often resulted in calls going to voicemail.

To fix this, we enabled "Do Not Disturb" (DND) on the SIP client while keeping Teams active for the extension. This configuration ensures that calls are handled seamlessly by Teams without interference from the SIP client.

Note: There's no need to disable the SIP client entirely—just activate DND on the SIP side to avoid conflicts while allowing Teams to manage the calls effectively.