Erase all contents and settings not working

Please follow this procedure for force resetting your iPhone ⇢

• Press and quickly release the volume up button.
• Press and quickly release the volume down button.
• Press and hold the side button until you see the Apple logo 

Please post back if needed. 

Hello~ Are you try to reset your iPhone? If so click on below…

How to factory reset your iPhone, iPad, or iPod touch - Apple Support

If you are try to force restart…

Force restart iPhone - Apple Support

~Katana-San~