phone not connected to network

Over the past several weeks I try to make a call and get the same message "Your phone is not registered on a network so yo can only make emergency calls".  I have to restart my phone each time this happens. The bigger problem is if someone is trying to call or message me and I'm unaware the problem exists. I've been told it goes directly into voicemail .

I have the Network Operators set to Select Automatically which it has always been since I got my Samsung s23. I recently change it to Xfinity Network Operators. Should I leave setting on Select Automatically or Xfinity Network Operators?

Has anyone else been experiencing this problem? 

Thanks