Hello and welcome to Windows Central.
This issue has been discussed numerous times elsewhere, both in these forums and in other websites. The only known working solution is to take your phone to a service center and have them diagnose the problem and replace parts as needed.
Other attempts that were tried with no conclusive results:
1. Connect phone to PC and run Lumia Software Recovery Tool
2. Keep phone in a hermetically sealed bag of uncooked rice for 12-24 hours.
3. Leave phone untouched for 6 hours, plugged to a charger.