Some Associations don't accept Amex or Discover Card. This customization gets overwritten with each roll-out, so I've detailed the steps below.
1. Goto Settings-Customizations-Customize the System
2. Click Entities-Payments-Fields-cobalt-creditcardtype
3. Remove the Credit Card Types from the value-list, click Save-And-Close, then on the next window, click Publish All Customizations.