When the lock screen interface will be gray short, then completely black screen

[wucuandada]

Is there anyone who knows how to solve the problem?

 

[bear7962]

Is there anyone who knows how to solve the problem?

Your iPhone probably needs a reboot. Plug your iphone into your computer via the USB cable, and as you open iTunes, press and hold both the top sleep button and the home screen button. When you see the Apple logo, release the top button, and then the home button.