Why can't I turn flight mode off?

[Windows Central Question]

why the flight mode couldn't turn off?

my l520 is error when i try to turn off the flight mode. so i can not use my sim card. can you help me whats wrong? someone said, i have to downgrade. my os is lcyan. and when error, i checking the extras-info and its ldenim. so, i downgrade my os. and now, its still error. omg

 

[Ed Boland]

Have the SIM card replaced. Your carrier should give you a new one at no charge. (AT&T does anyway) If that doesn't fix the problem, and your carrier isn't having any tower issues in your area, your phone's antenna/radios may have gone bad. Mine did just that.. ended up having to have the phone replaced under warranty. Check your warranty status; you might have to use it.

 

[RumoredNow]

You might want to try this: http://forums.windowscentral.com/nokia-lumia-1520/299878-3.htm#post2853178

It seems this new problem has been cropping up and the motherboard/daughterboard stop talking to each other... The "trick" in the link gets them back on track.