There are occasional errors in the traditional banking system. Usually, this is the result of a bad account number entry, using the wrong type of account (a brokerage instead of a banking or checking account), or having your bank reject the Swan withdrawal due to triggering some issue on their end.
You should have received an email explaining the source of the error and how to correct it to re-enable your account. Once you update your plan, make sit says "Active" on your dashboard. If the plan is indicated as paused, then click the "Activate" link to re-enable it.
If you need to move the date of your next ACH transfer, please contact us at firstname.lastname@example.org.