How to stop LG G3 from reseting after inserting SIM card

[mehmod288]

I put a sim in then it's been constantly restarting or turning off by itself. Sometimes it'll stay on for a couple hours before turning off again or sometimes it'll just turn off again as soon as it turns back on. If I leave it on airplane mode or not have the sim in, it will work perfectly fine

 

[belodion]

Have you tried more than one SIM?

 

[ratsttam]

If your carrier can get you a different sim (they do go bad and make the phones do weird things), and see if that helps, that is great.
If that doesn't help, than there is very likely a hardware issue with the radios in the phone, and it'll need to be replaced.