Screen turned off but didn't lock

[AC Question]

I'm using a Samsung Galaxy Note 5. After i upgraded to Nougat, sometimes after i used the phone, i didn't lock it. (screen timeout have been set to 1 minute) In 15 minutes later, i want to unlock my phone. However, it's unlocked already. I didn't put my fingerprint yet. I need to lock my phone manually. It's really annoying when i forget to lock my phone. Can anyone help me?

 

[belodion]

After what period of time is the screen set to lock? https://forums.androidcentral.com/showthread.php?t=409154

 

[B. Diddy]

Welcome to Android Central! Is Smart Lock turned on?