How to restart iPhone 13 Pro Max

• Press and quickly release the volume up button

• Press and quickly release the volume down button

• Press and hold the side button.

• When the Apple logo appears, release the button.

Force restart iPhone - Apple Support (IN)

Press and release the Up button quickly

Press and release the Down button quickly

Hold the Side button in for at least 20 seconds, then release and the phone will restart (Ignore the slider when it appears and keep holding until the Apple icon appears in the center of the screen, then release the Side button)

More info here: Force restart iPhoneApple SupportOfficial Apple Support › guide › iphone › ios

If you try this sequence a few times and it does not help, this likely indicates that there is a hardware problem with the iPhone and you should make an appointment at the Apple Store / Genius Bar or an authorized Apple service shop.

You can find a list of authorized shops in your area using this link:

Find Locations

What happens when you try to start it? Any error message? Have you tried a forced restart?