Sorry to necro this thread, but I was losing my mind trying to figure out why my fingerprint sensor wasn't working. It's not a 6p, but the GS8A, but the solution was the same. My sensor would work while unplugged, or charging at home, but come to find my budget bin car charger somehow interfered with the sensor, and as I'm typing this, it apparently messed with my touchscreen as well. Grabbed a quality car charger and both sensor and touchscreen work leagues better.