I checked all sides. Azure, local sbc network, port configuration. Just to make sure. There was no change. Ports are working.
During trouble shooting I did the following:
- restarted Azure machine of 3cx phone system
- performed the 3cx integrated firewall check (successfully)
- restarted local router
- tested port availability for sbc successfully
- resetted the phones on sbc site
- deleted and the rejoined the phones on SBC site to 3cx phone system again.
- changed SBC from TLS to TCP (
@SteveITS ) , pushed config, restarted the sbc
- changed SBC hardware with spare RaspBerry.
- added a new windows driven SBC to phone system for testing purpose and used it instead of RaspBerry SBC
No steps from above has helped solving the issue. I'm out of ideas especially because this issue just started after updating to latest sbc version.
Again: If I change a single phone in network to use STUN direct conneciton it works perfectly without issues.
Any help is highly appreciated,working phones are urgently needed.