Generally they are able to resolve quickly so you can resubmit payment. Here are a few common reasons we see for ACH payment failures:
The account doesn’t support online transactions (certain savings accounts or money market accounts don’t allow for online payments)
The account has a maximum number of monthly transactions – some institutions only allow for a limited number of online transactions per month
The transaction is over the daily max withdrawal (many banks have a limit of $1000)
There are insufficient funds to cover the payment