Right after upgrading my iPhone 12 Pro Max to iOS 14.6, I have lost cellular data. I called TMobile customer service technician who sent me to the store. The store representative replaced my old SIM card with a new one and talked with a technician on the phone for half an hour, still couldn’t solve the problem. I reset my 12 Pro Max to factory setting, unfortunately, the iOS stays at 14.6. I have to put the SIM card to my old iPhone Xs Max on 14.4 and use my old phone.
Is there anyone else having the same problem?