Hi guys, sorry if this was asked as there's 90+ pages here. But I just got a Redmi for my mom yesterday, and sometimes, when I locked the phone and i put it aside, then tried to unlock it again, it went blackout. I can still feel the sensor and stuff, but the screen just keep blackout. Can I know what's the cause of this?

hi bro, the issue been solved. this is due to my mom inserting a sd card which is not suitable and causing it keep going blackout. once the card taken out, the issue gone.