1. The screen is grayed out. Maybe you set the sleep time/stop time for healthy use of your mobile phone and turned on the grayed-out switch. After a limited time, the screen will turn gray. It is recommended that you turn off this feature.
2. The screen turns gray. Maybe you turn on e-book mode. When turned on, the scene for reading and text will turn gray. If you don't need it, you can turn it off. Closing mode: enter Settings, search, click E-book mode, and close E-book mode.