I have set up Freepbx on a remote (AWS) server and trying to connect my local Yelling T46G phones to freepbx. I am using the paid version of End Point Manager.
As far as I can tell, I have the auto provision set up correctly and the phone connects to the system but whenever is choose the “Save, Rebuild Config(s) and Update Device”, the phones don’t update or do anything.
Take a look at Firewall → Services → Extra Services. I’ve noticed that even if extensions at dynmaic IPs get their public IP whitelisted you still need this set up correctly.