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.
Had you already tested turning off Safe Web, or did you reinstall to test?
If you had VPN turned off and also had Safe Web turned off, there is nothing else I can see in Norton 360 that could be blocking any connection.
You mention this started around the update to iOS 16. Maybe there is something Apple changed in the handling of cell to wifi transitions. Have you checked all your settings in regard to the wifi calling?
The internet security was off and the problem still occurred. so far with the Norton app deleted everything seems to be working. Thanks for your help. I still want to use the Norton app, but can't until someone can help me figure out the problem.
If you are turning off the VPN and that makes no difference, I would suggest that the VPN is not the cause.
One thing I can suggest to help diagnose this issue is turning off the Safe Web feature in Security > Internet Security. That has been known to cause different connection issues. Turn Safe Web off and test your wifi calling again.