Solved No audio on forwarded calls

[ckatterl]

Dear all,

I have a very strange issue.

Incoming calls are coming in via ISDN (multi).
Outgoing calls are routed via SIP-provider.

Everything for itself is working perfectly.
I can receive external calls without issue, I can place calls from int to external without issue.

BUT:
When I receive an external call, I answer it..and then I am trying to forward it to some mobile phone. The mobile phone then will not hear anything. The other side (caller) can hear me, but I cannot hear anything.

When I configure to be outside (via 3CX Client) - and set "forward to my mobile", the issue does not occur and everything is perfect.

In both situations, calls are coming in via ISDN and going out via SIP.

I tried to route outgoing calls via ISDN and do the forwarding-game then. With this configuration, it's working normally...

Any ideas?

BR, Christian

 

[ckatterl]

BTW, I tried if the update to 15.5 SP5 will help, but it did not.

 

[YiannisH_3CX]

Hello @ckatterl

As a first step make sure that under the SIP trunk settings / Options PBX Delivers Audio is enabled but the options Supports Re-Invite and Support Replaces are not enabled. Then try the same test.
If the issue persists ensure that the gateway has the same options.

 

[ckatterl]

Hello,

it seems that this is the solution. I don't know why this happened because the setting has always been like this.
PBX delivers audio was always selected and support re-invites/replaces was ticked too. I removed the re-invites/replaces now and it seems to be working.

I will monitor this.

Thanks a lot,

Christian

 

[YiannisH_3CX]

Glad to see the issue has been resolved. Let us know if you face any more issues