Hi, I also have this problem. Just bought an iPhone X a month ago. Ever since I’ve installed iOS 14 it keeps saying “Cellular Data Not Subscribed To Data Network.” It worked prior to the update 2 weeks ago. I have tried all of the following: Called service provider Reset network setting Turn off/on airplane mode Turn off/on cellular data Hard reboot Soft reboot Reset content and data Turn off/on roaming My phone is practically useless now. Which sucks because I have to use it while working from home.