I am using Dynamic DNS module for FreePBX, which creates a xxxxxx.deployments.pbxact.com address that SIP clients can use for registration.
Until now, I have only used Chan_SIP extensions, on port 5060, and have not had any problems with registrations.
I have now switched to PJSIP and devices stopped registering through DDNS address.
I have tried changing PJSIP port to 5060 and restarting asterisk – still does not work.
At the same time, devices register successfully if on local network through local IP address and port on xxx.xxx.x.xxx:5061 or :5060 respectively, depending on which port I am using for PJSIP in FreePBX SIP settings.
So it is specifically DDNS problem.
Any ideas on how to solve it or is it a FreePBX bug?