Trouble with cyanogenmod

[Jabbadab]

Hi, I dont know if this is the right place to ask, but I've been having some trouble with my Samsung Galaxy S4 lately.

About a year ago, I installed cyanogenmod, and everything worked fine. But about a month ago, every time i locked my phone, I would lose my signal.

The only thing that makes the signal come back, is turning on and off flight mode. The weird thing is that this only happens when I'm at work or away from home. Although it says i have no signal, I am actually able to recieve calls, but not make calls to other people.

I have tried going into testing, but I dont really know what I'm doing.

 

I would really appreciate some help

[XrayCy]

do you have any app that close programs enhance performance like grenify 

[Jabbadab]

do you have any app that close programs enhance performance like grenify 

No, I dont.

[Thx And Bye]

What Version of CyanogenMod-Version are you using?

Did you change or use the Developer options?

 

It also may be a SIM failure, i had the same issue but also got errors when trying to access the SIM card settings.

But it really has to be a setting located on the SIM-card, like Call forwarding.

After i got a new SIM i didn't had any problems with losing connection after wake. (and reading / changing settings on SIM)

If you get some window like this, it is reading from SIM: