Why i cannot select network operator

[Seb Edouard]

I have a phone samsung A7 my sim were working fine til today.it says mobile network not available although the sim is recognised on.my phone.i have gone to mobile network and search automatically.it says connection failed try later I have also restore factoring still no connection 1 null on the icon on the sim. In another phone the sim works.please help me

 

[Rukbat]

First call the carrier. It they have a tower out of service, that could do it.

If not, bring the phone to them and ask that what's going on. The SIM card "chooses" the network operator.