Take out the SIM card, check if it is damaged, clean the chip and put the card back into the slot again, or try another SIM card on your phone to see if you fixed the issue.
Mismatched chargers, higher ambient-temperature conditions and incorrect activities might cause the above issue. Make sure to use original power accessories (power adapter and USB cable) that are compatible with your phone.
Check your power adapter and USB cable for signs of damage, if there are, stop using the damaged ones and buy new ones in time, or try other accessories on your phone, and see if you fixed the issue.
Do not charge your phone with third-party accessories, for your phone and its firmware might damage because of the different specifications.