Anytime you can enrol and use the administrator successfully but cannot enrol or recognize enrolled additional users it is due to a bad enrolment process.
Enrolment for users after the two administrators is done differently. The trick is when you enrol the 3rd user make certain when the admin places their finger to wait until the sensor light goes dark and immediately place the finger of the next person. That person should not move their finger until you hear a LONG beep. When the user 3 places their finger ensure it is in the centre of the scanning pad and an even pressure is applied to the centre of the pad from the centre of the finger (not the tip).
