Try turning the phone off and eject the sim.
Then try the sim in another phone to see if it works fine and if it does then re insert the sim in your phone and reboot to see if that helps @weary
Also try resetting the network settings in your General Management section.
Daily Driver > Samsung Galaxy s²⁵ Ultra 512Gb ~ Titanium Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "
