the mic seems to be mute when calling

Which telephone are you using? Which router? How is the phone connected to the router? You are sure the microphone is not muted or tunded right down on the phone? Have you tried restarting the router?

Hello @JamesZh ,

it’s a good sign that calls are getting through in general and you hear the other party. That still leaves quite a few parts where the issue could lay, bs0 has already asked some pertinent questions, I’m sure we’ll be able to have you calling again in short order.

Kind regards, Sven