I have a problem with my LG G2 (D802). It shows, without reasons, no network signal and no SIM. I do an hard reset but nothing changed. What's the problem?
There could be different causes:
The SIM card has no connection to your device. Maybe it has moved or would not be inserted correctly. It is best to remove the card and reinsert them.
The SIM card is broken. It is best to test another sim card or to check the own card function in another device.
The smartphone has a defect. It needs to be repaired.
There may be other sources of error and better investigation methods.