Solutions to fix-
First solution: Forced Reboot your phone
If your phone got stuck or frozen on any screen, the first thing you must do is make it respond again and this is the best solution, so far. A forced reboot is a simulated battery removal which forces your phone to turn off and power back on. It will also refresh its memory as well as reload all its apps and services. Here’s how it’s done.
Press and hold the volume down button and don’t release it.
While holding down the volume button, press and hold the power key as well.
Keep both keys held down together for 15 seconds or even more.
Your device will reboot after this and get out from being unresponsive or frozen. If you don’t want to troubleshoot the problem, you may continue using your phone and just do this very same procedure if the same problem happens. However, if you have time and you want to fix the issue so that your phone would no longer become unresponsive or frozen, then move on to the next procedure.
Second solution: Observe your phone in Safe mode
Depending on how frequent the problem occurs, you may be able to isolate it immediately by going into Safe mode. This will temporarily disable all third-party applications so if the phone works perfectly fine while in this mode, then it means that the cause of the problem is a third-party application. You may continue your observation in normal mode and be mindful of the apps you use to know which of them is caused the phone to become unresponsive or frozen. If you already have an idea as to which of your apps is the culprit, then you may uninstall it or just reset. Here’s how to run your phone in safe mode:
Press and hold the power key until options show on the screen.
Tap and hold the Power off option until the icon changes into safe mode.
Tap Safe mode to restart your phone.
When the phone has booted up, you will see the text ‘Safe mode’ on the lower-left corner of the screen.