Call cut outgoing and sometime voice interuption

Hello All,

I have multiple asterisk server installed and I have some generic issues with them.
The call are cut. I am on thephone speaking and I have a blank (cannot hear the other side).

Is there a specific reason or a way to improve. I thought it’s link to the internet connection but this last one has good upload (more than 2) and download???

I have also another strange issue with only 1 of my server. I have several outgoing calls that are cut (Stopped) during the call. At the other side it’s like the call is not cut but I am not anymore on the phone.

Can it be an issue on the central?

One way audio on VoIP (I had to infer this) is normally caused by NAT or firewall configuration issues.