I have an iPhone 12 running IOS 16.11 and using WiFi calling when the cellular signal is week and Norton 360. i have the following problem. after a while ,a day or less, from a reboot when I try to make a call I immediately get a message "call failed." Upon a shut down and reboot I can make calls. When this happens I also can't receive calls, the calls go right to voice mail, since i have no indication of the problem in advance it is most infuriating and dangerous. I have tried turning off the VPN and that does not seem to help. I think that the problem occurs when switching between WiFi and cellular calling. I have deleted the Norton 360 app from the phone and that seems to have solved the problem, however I like the idea of the Norton protection. Since I don't know when my phone calls are blocked and I go from WiFi to cellular call many times a day this is a real problem. It is possible that this began to happen when I upgraded my phone to IOS 16.