I'm on Samsung Galaxy S7 Active and running Android 7.0 and I was having the same issue. Since I didn't find the "Automatic Lock setting" mentioned before I had to kinda look around and found the option. It is not clear and I really wish they would just make a separate option for this but that's not the case for now. Settings -> Lock screen and security ->Secure Lock settings -> Secure lock time -> chose option "Instantly with the power key or when the screen times out" In my mind it makes sense that then it would prompt me to chose how much time until the screen times out but it doesn't. To pick this time you actually have to go to another settings option settings -> Display ->Screen timeout -> you can pick from 15 sec - 10 minutes Hope it helps!