You are not able to add or edit a payment that has a designation on it that is currently inactive. If you need to continue using this designation for new payments, or to edit existing payment, you will need to make it active again.
  1. On the Fundraising tab, click Fundraising Hierarchies
  2. Click the drop-down next to the inactive designation and click Mark Active
  3. On the pop-up window click Yes
Now that the designation is active, you should be able to add or edit a payment with that designation.