Device is not getting locked automatically

[Android Central Question]

Im using Moto G5S Plus.My question is that why is the phone doesn't locks itself automatically, why every time i have to do it manually by pressing the lock button .It was working fine earlier suddenly it's not working

 

[B. Diddy]

Welcome to Android Central! How long is your Lock Automatically interval set to? That's how long it takes between when the screen goes to sleep and when the phone locks. If it's set to something long like 30 minutes, then the screen has to be off and the phone idle for 30 minutes before it locks again.