A faulty SIM cardon your cellphone might also cause no service problems, searching, and other associated errors. This could happen as a result of a big system update. Fortunately, such issues can be readily fixed by simply by replacing your iPhone's SIM card. Here's how you do it:

1. Completely turn off your iPhone.
2. Insert the SIM ejector tool into the little hole on the SIM tray on the side of your phone while it is turned off.
3. Push the tool gently until the tray ejects.
4. Remove the SIM card from the tray and set it aside. Also, look for any visible signs of damage, such as scratches or liquid traces, on the card. If there aren't any, replace it in the tray in the same arrangement as before.
5. Make sure the SIM card is seated properly.
6. Then, until the phone locks, push the tray back into the phone.