do one thing take your SIM card out and waiting for a minute and put it back and do rebooting your phone - This one is quick and simple. Make sure your phone is off before removing and reinserting its SIM card.
Remove your phone’s battery - Some phones have removable batteries. Sometimes removing and reinserting the battery can fix certain issues. Just make sure your phone is off before you do this.
what is mean for Rebooting the phone means to turn off your phone and turn it back on again.
please put it more explanation what is your issue !
Good Luck
