It is always possible that the magnetic reader down in there that reads the magnetic encoding on the Credit cards is damaged. Swiping cards is not the way to be taking payments for many years now, tap or dip is the secure way and they way you won't automatically be held liable for chargebacks. Swipping should only be used for if tap or dip won't work. Both are extremly fast and easy to do. Only a couple years left and all magnetic cards will be phased out and no longer made. The US is a decade behind on the switchover to tap and chip.
