What is the problem with the cell phone not having a signal?

1, the phone has no signal, it may be the settings on the phone, look at the click on the flight mode to turn it off to reappear the signal.

2, when the SIM card is in the case of not inserted properly, there will also be a cell phone display no service problem. Pull out the SIM card and re-insert it. If the SIM card is bad, it will also show no signal.

3. There may be a problem with the network system. Restore the network settings. Wait for the phone to reboot and see if there is any signal.

4, when entering a confined space such as an elevator, there will also be no service. Then again, this can also happen when going to climb mountains or deserts and other wild mountains. When you leave the area, it will return to normal. If it doesn't recover just reboot.

5, restore factory settings or no service, may be the phone hardware failure, then you need to go to the phone after-sales service for further maintenance.

Reference:

Signal - Baidu Encyclopedia