A recurring donation can fail for a number of reasons such as an expired or cancelled credit card, etc. If your site is taking recurring donations, you need to set up an email response with directions to the donor on what to do if their donation fails. If a donation fails once, it most likely will fail again in the future. The best recourse is to have the donor login to your site, disable the current recurring donation and create a new one.

To set up the email response, login to the admin side of your site and go into the Donations App --> Email Messages tab.  This is your list of emails used for the Donation App. If you have an existing email that would be appropriate for a failed transaction you can use that one. Otherwise create a new one via the Email Message Add tab.  If you want an Admin to receive a copy of the email as well, you will need to add their email address to either the CC or BCC fields.

Once the email has been created, you can go into any donation campaign that allows recurring donations and select that email from the dropdown list for the Failed Recur Email Message field. If a recurring donation fails processing, the donor will be sent this email for this campaign.