For about 12 hours, I was unable to make calls from my iPhone 11
I can understand why my iPhone 11 might have been unhappy with me. Yesterday I spent several hours in an area with little to no cell service, occasionally trying to make a call, but never succeeding. Then I found a strong WiFi signal and connected to it. Data worked fine. Couldn't connect a call. WiFi calling is enabled. Returned home to good cell service and great WiFi, and still couldn't connect a call. This morning, still couldn't connect, despite turning Airplane mode on and off, and restarting the phone. A couple hours later, everything suddenly went back to normal.
Phone problem? SIM problem? Carrier problem? Any ideas?
iPhone 11, iOS 14