Try these solutions
Power off & on
Yup – sounds silly however this is the most common solution to a lot of issues. Simply hold down the HOME button and POWER button at the same time for 10 seconds. You will see the device logo come up & let it reboot
Check it's charged
Charge it up (if you can) & see if this fixes the issue. Not a common solution but still worth double checking
Check the time & date
Check to see if the time & date is correct. If it’s not make sure you can connect to a wifi or hotspot so the iPhone settings can sync with the server.
Devices are so important it’s hard to live without them. Remember to try answer all questions in this form. We are here and on your side to assist so rest assured we will try our best possible
No receipt No warranty
Unfortunately under no circumstances can any repair be covered under warranty without the receipt or invoice.
Back up your data
If possible, back up your data. Remember this issue is post damage and post technical work which could be something that may manifest over time.