We have a Yeastar N412 running on one of out customer site. Now we have a issue with that device, for some reason when i try to configure a setting under PBX -> Advanced Settings -> SIP Settings it will not save the changes.
When i login via the CLI to the Yeastar PBX and check the pjsip.conf file it is empty.
With TCP dump i do see that IP Phones are trying to register, but the system is sending ICMP unreachable as respone.
It looks like the Asterisk service is not running in a correct state and is loading a empty pjsip.conf file.
I tried to update the firmware to the same firmware version so that the system would restore the software (System is running on latest firmware).
Did anyone ever experience a issue like this or does someone have a idea what this could be?