Greetings All, I want share with you My fanvil Ip phone firmware is not supported . I tried to update Firmware From 3cx but its not fixed after restart phone has same problem.
If it doesn't work, factory reset the phone.
Download the correct version from here https://www.3cx.com/support/phone-firmwares/
Then login to the phone web interface, and upgrade it manually.
When done, you can assign it in 3CX again and it should now be ok.