Constant NO SERVICE message

I get " NO SERVICE" notification constantly, cannot remove it or anything. Both sim cards are working. both have internet connection.  When I force stop the SIM manager application the notification goes away but it comes back when I unlock the phone next time.  What can be causing this problem ? How can I solve it?

thanks

last edited by Arsen

Today discovered that if I disable both sim cards from sim manager and restart the phone, the NO SERVICE message will not appear even afther I turn on both sim cards again. It will not appear anymore until i lock and unlock the phone again.  Maybe it is somthing caused by security programm or some hibernation finction?

Meizu m3s

Do you have an IMEI?
Which firmware are you running?

Try reinstalling the firmware or updating with cleardata.

Looks like your connection to Meizufans was lost, please wait while we try to reconnect.