For more information about why a transaction was rejected we can view the details of a transaction:
  1. Log into the BBMS web portal at https://bbms.blackbaud.com
  2. Click Transactions > Transaction search
  3. Enter the information available such as the date of the transaction or the name of the card holder and click Search
  4. Click the ellipsis next to the transaction and select Details
  5. The Gateway Result value will provide the full decline message

See What are the decline or rejection codes for BBMS? for a description of each decline message.