Restart the phone
Press and hold the Power button
Tap Restart or Reboot
If there is no restart option, power off the phone
Wait 30 seconds
Turn the phone back on
Remove any case or accessory that may press the volume buttons
Check that the volume buttons are not stuck
Uninstall recently added apps
Clear any dust or debris around the buttons
If the phone is still in Safe Mode, perform a normal shutdown and power on again
If needed, back up your data and factory reset the phone