Key Rules
Kicking Team: If the kicking team recovers the muffed punt, the ball immediately becomes dead at the spot of recovery, and they cannot advance it. [1, 2]
Receiving Team: If the player who signaled for a fair catch (or a teammate) muffs the ball, the player retains a protected opportunity to catch the loose ball before it hits the ground. If the receiving team catches or recovers the muffed ball after a fair catch signal, the ball is dead at that spot and cannot be advanced. [1, 2]