I have found a couple of forum posts mentioning what seems to be similar issues, none I found have solutions and they are closed for additional updates.
https://www.3cx.com/community/threads/fanvil-handsets-freeze-periodically.76433/ -Posted Sep2020, closed for replies...
Hello:
I was hoping that someone could assist me with further suggestions in troubleshooting. I have one phone namely our receptionist's phone that will spontaneously reboot in the middle of a call. It is random and there is no consistency with the interval at which this happens. The one...