Screen dims when I'm watching videos
When I'm watching a video, the screen dims and phone will power off. I have to tap the screen every minute to make sure it doesn't power off, which is very annoying. I would assume the phone knows I'm watching a video and won't power down. My auto brightness is already disabled, hard resetting doesn't solve the problem, and this happens on any app I'm using: Youtube, photo album, etc. My iPhone 6s is new, just got it a couple months ago. I've just recently started to notice this problem. What's wrong and how can I fix this?
IPhone 6s iOS 9.3.2
iPhone 6s, iOS 9.3.2