A red light indicates a feedback loop condition called oscillation. To fix this, simply move the antennas further away from each other, then reset the booster by powering it off and back on. If you still see red lights, then you may have to move them even further away with the same
If you gave red and green blinking lights, check your signal on your phone and see if it’s improved. Red and green lights are okay if you’re amplifier is working and offering you enough coverage inside your home or office.