My gut feeling is that this is MicroSIP’s fault, but what do I know?
When we place voice or video calls between extensions everything works as expected. But when they try to send a text message while in a call, they get another call notification pop-up from the IP address of the server, not from the sender’s extension. If they then accept that call, the original call drops. But they still do not receive any text messages. The sending side gets ‘accepted’, and that’s it.
While not in a call, they get the same pop-up from the server’s IP address, accept it, see text message/log window and that’s it. The message being sent does not appear on the recipient’s window.
Is this caused by something that I misconfigured on the freePBX or MicroSIP just cannot exchange text messages via SIP servers?