Iphone 6 Won't turn off automatically?

My iPhone 6 won't turn off automatically! Ok, so, for example, I turn my phone on to check my messages. Once I finish checking my messages I press the home button. And leave my phone on the home screen then set it down (While it's still on the home screen) and if I walk away for even 15 minutes it's STILL on. It will only turn off if I do it myself. My other iPhone hasn't done this!

You need to go into settings then Auto-Lock then set how many minutes you want it to lock at.

Find the "Settings" app, tap it; tap on "General;" scroll to "Auto-Lock," tap it; select how long you want the screen to remain on after the last use (activity), by tapping it. To return to the home screen, push the physical round "home" button at the bottom of the screen (but you already knew the latter, right?).

Hope that that helps.

Thank you!