If an ACH transaction fails, it will be voided automatically.

Realm will not notify you unless you've opted to be. Depending on the bank, it may or may not notify contributors about any returns. Vanco will always notify the church but will never email contributors directly. It's up to the church to decide how it wants to communicate this.

If a one-time gift doesn't process, contributors are notified by message at the top of any Realm page.

If a scheduled gift doesn't process, contributors are notified by email, and their unprocessed recurrence is placed on hold. From the email, they can sign into Realm and adjust the payment method.