Small row of touchscreen sometimes unresponsive

Basically, near the favorites tray, a small row of the touchscreen sometimes is unresponsive. Strangely, the very top of each application on the favorites tray is responsive. Unfortunately, when this portion is unresponsive some things are "untappable". In developer mode this portion of the screen receives input even when everything else doesn't seem to. Is this a software glitch or is my hardware faulty? Thanks! Also, I'm running Android Marshmallow 6.0.1