Does anyone have a suggestion as to why I suddenly cannot connect/stay connected to a network?

[AC Question]

So I've had my Galaxy S6 for 1 year 6 months now, and have the international version (G920F). About almost a week ago I've suddenly started having No Service/Emergency Calls Only, I suspected it was my provider being weird but it wasn't the case as I was having that issue EVERYWHERE I went (about 50 miles/80 km away from home even) even in popular areas. Provider sent a replacement SIM and had issues with that, and oddly enough I actually wanted to change service provider anyway and even with this new service provider, can't seem to get any connection.

I have tried everything from keeping it in airplane mode, rebooting it, messing with the mobile networks (it picks up AT&T which I'm using right now however says "Unable to connect" like it can't register to the network, occasionally it will connect but go back to No Service in about 30s tops. My IMEI and S/N are still valid and I have rooted my phone and it is in Android 5.0.2 still. Samsung support and my network provider support has been tried and none of their troubleshooting worked. Also I have tried rebooting to phone to factory ROM and the problem still persists. Sadly, I cannot send it to Samsung since I have rooted it and I'm also unable to update to the latest software version due to KNOX being tripped.

Any help/suggestions would be greatly appreciated.

 

[jasonandrews25788]

Is there such an option on your phone if you wanted to connect/register to your carrier automatically or manually? Make sure it's automatic. It could have been set to manual. Meaning it will hold on the cellular tower it is connected to. If ever that you'll be away from that tower it will not automatically connect to other cellular towers.

 

[pumaguerrero]

Hi there
I am having the same problem, i have my phone for 8 months now, it is unlocked and also rooted with tyranus, so no guarantee, and my problem started right after i came back to the UK from the US.
In the US i was using AT&T and as soon I landed and swaped sim cards the phone stop receiving network signal.
I've also tryed everything, from switch off the phone, airplane mode, played with network settings, reset all settings, reset to factory, reinstall rom, sim card replacement, etc... and nothing seems to work.
I checked imei status and is still unlocked and is not black listed as I bought it second hand.
Any help or ideas?
Thank you!