Phone keeps dying even with new batteries

[MTHall720]

I have a Samsung Galaxy Note 4. I purchased both a Samsung battery and an Anker brand battery. Phone keeps turning itself off at least once a day. I have to take the back off the phone and reinsert the new battery I just got. Same story with my previous battery.
Any clues what the problem is?

 

[Andrioduser11]

Check to see if the contacts where the batter connects isn't loose or has gunk on it