Huawei Y7 keeps restarting?

Have a Huawei Y7 (TRT LX1 model number). Since 2h my cell phone keeps turning off as long as it is in idle mode, i.e. The screen is turned off. If I do something on the cell phone it does not switch off as soon as I switch the screen off and put it away, it usually does not take longer than 60s-30s until it starts again. While I was writing this, it suddenly switched off I have no idea what's going on.

Did you download something new or did the cell phone get an update?