Originally Posted by iAdam

It is automatic. Simply make sure that the AAdvantage # associated with your credit card is on the reservation. At check in, the computer will automatically recognize your CC benefit and allow you to check in 1 free bag (for up to 4 on the same reservation). Same applies for the priority boarding, when your boarding pass prints it will be reflected on it.

Your card must be active for about 7 days prior to the flight (I believe). I know my parents did not get the baggage benefit once but you can dispute it with AAdvantage desk and they will refund the fee. As for the priority boarding not working... I'm not sure you can do much except reach out to AA and make sure it gets fixed before your next flight.