No Ringback on internal calls (Only when activate Music on Hold)

Hello,

at the moment we have some new problems with our FreePBX 17 system. Most times now when you make an internalt call you can’t hear the Ringback it’s silence until someone on the other side pick up. I’ve made some tests with the Follow Me module and set a “Hold on Music” this is most times hearable. That problem is very strange.

Sometimes when i call back with the other telephone you can hear it and then the first telephone is also working until you save some changes. I’ve tested and debugged a lot but i can’t find a schema that can cause this error.

I’ve enabled the debugger and the first line when the call starts is:

RTP Packet Debugging Enabled
[2025-07-30 12:48:16] WARNING[150314][C-000001b5]: taskprocessor.c:1225 taskprocessor_push: The 'stasis/pool-control' task processor queue reached 500 scheduled tasks again.
[2025-07-30 12:48:16] WARNING[150314][C-000001b5]: taskprocessor.c:1225 taskprocessor_push: The 'stasis/pool-control' task processor queue reached 500 scheduled tasks again.
[2025-07-30 12:48:16] WARNING[150314][C-000001b5]: taskprocessor.c:1225 taskprocessor_push: The 'stasis/pool-control' task processor queue reached 500 scheduled tasks again.
[2025-07-30 12:48:16] WARNING[150314][C-000001b5]: taskprocessor.c:1225 taskprocessor_push: The 'stasis/pool-control' task processor queue reached 500 scheduled tasks again.

Is it possible that this causes the problems? We don’t have high load we have only some telephones and 2 oder 3 calls in parallel.

Perhaps someone had this problem and knows a solution. We use a Vodafone SIP-Trunk and the Inband Progress is off (But that should not be relevant for internal calls).

At the moment i have enabled the Follow me on all phones and uploaded a Hold Down Music with the Ring tone and set that. This resolved the problem at the moment.

It is possible that this problem is caused by the Yealink DECT System that had problems in the past perhaps that doesn’t fetch the ring request.

I hope someone has an idea.