Callers can't hear after on hold

[groupe10]

We are having an issue while we are talking with callers and a second line is ringing. We put the first caller on hold and we get the second caller. When we want to return with the first caller, he can't hear us. We can hear , but the caller can't hear us.
3CX V15.5.15502.6

phone that we are using is grandstream gxp-1782

 

[AWS2P]

Hello,
Why not trying to move PBX to latest release V16.6.655?

 

[cobaltit]

3CX Supported provider? Firewall test passing?

 

[JohnS_3CX]

Hi,

Ensure your trunk has these options disabled, and then test again.

 

[groupe10]

Provider is VOIP.MS and here is the firewall test

 

[groupe10]

Hi,

Ensure your trunk has these options disabled, and then test again.
View attachment 19077

Those two options are disabled yes.

 

[JohnS_3CX]

Hi,

Please check your RTP port range, it appears some audio ports are blocked by the firewall.

The entire UDP range to forward is 9000 to 10999, and then run your firewall checker again please
https://www.3cx.com/docs/ports/