stuck on select a wireless network

To power off hold the side button (SLEEP/WAKE) until "Slide to power off" appears. You will need to hold for 5 to 10 seconds.

Oops, I just saw that you have an iphone 8. To do a force reset: Press and quickly release the Volume Up button. Press and quickly release the Volume Down button. Then, press and hold the Side button until you see the Apple logo.

What happens when you tap Cancel?

And what happens when you: Press and quickly release the Volume Up button. Press and quickly release the Volume Down button. Then, press and hold the Side button until you see the Apple logo.

If you ever have an issue where you cant turn your phone off default to holding the power button and vol down button and it will do a "soft reset" nothing will be deleted just a simple turn off turn on 🙂 hope it helps, if it did click helpful!

thanks

Are you holding the side button long enough (10-15 seconds)? If so, and it still doesn't restart, your phone is broken. Fortunately the warranty is one year, so contact Apple Support using the link at the top of this page and arrange for a replacement.

How are you trying to power off?

That doesn't work on an iPhone 8.

Did you see my corrected post?