IPhone 7 is in Diagnostic mode explain

Hello leroy71,

Thanks for using Apple Support Communities. From your post, it sounds like your iPhone is stuck in diagnostic mode.

If there is a blue bar at the top of your display stating there's a diagnostic being ran try clicking on the bar and hitting end diagnostic this should allow you will exit the diagnostic being ran on your device. If your device is frozen on a diagnostic screen the following article will walk you through some troubleshooting steps:

If your iPhone, iPad, or iPod touch won't turn on or is frozen

If you require further assistance after following these steps, please contact Apple Support.

Hope this helps! Cheers.