If your donation form is setup to use donation levels that allow the creation of recurring gifts, then the form must use a merchant account that supports recurring gifts as well. You can verify this is the issue by going to step 4. Validate on the donation form setup, and clicking the validate button. If this is the issue, you will see the following message upon validating your form:

"The merchant account for this campaign does not allow recurring transactions. When using flexible sustainer, make sure that the merchant account for this campaign allows recurring transactions."

To change the merchant account to one supporting recurring transactions, edit the donation campaign by following these steps:
  1. Go to Fundraising > Donation Management
  2. Find and edit your campaign
  3. Go to step 2. Choose Financial options
  4. There on financial options, edit item 1. Merchant Account to select a merchant account you have setup to accept recurring transactions.
To check which merchant accounts are setup to support recurring donations navigate to Setup > Payment Capabilities

There you will see a list of all of your merchant accounts, and there will be a field for Sustainer with a green checkbox for merchant accounts that do support recurring transactions, and a red X for those that do not.

If you need to edit a merchant account to set it up so it allows recurring transactions follow these steps:
  1. Click Edit beside the Merchant Account name
  2. Click on Step 2. Merchant Details
  3. Mark the checkbox for "Support recurring transactions"
  4. Click Save to save your changes