I have a cloud instance of freepbx. I can call other users fine using grandstream wave. I can call out on my sip trunk fine. One user, a very important one, I cannot hear. She can hear me. We have the classic one way speech issue. I have a sonicwall and I have no issue. Not sure where to begin.
BTW I am finding the Grandstream wave to be good for me but spotty for others. Requires reboots to keep in good service and stay registered. Sometimes on 4G no registration at all. Who knows.