Mine started this morning - Received an SMS message while on cellular network on my way to work. Picked up the phone to look at the message when I go to my office and had no signal and it just keeps searching. The signal here at my office is always very good. I headed toward the AT&T store to ask if there had been any issues; got another text on the way so I turned around and headed back to the office. Same result. Arrived in parking lot and the signal disappeared. Others in the office with the same AT&T service are surfing along on the internet and making calls. I got squat. I have no idea why it suddenly just stopped getting a cellular signal. I've tried rebooting, changing the roaming setting, cellular setting, wi-fi even (but we don't have wi-fi here). I have 14.5.1 installed on the iPhone X. Anybody got any ideas on this?