The Tenant owns the responsibility to resolve payment rejection/return issues. Please ask your Tenant to discuss the payment rejection/return directly with their bank.
Link to ACH return codes, reasons, and details : https://www.vericheck.com/ach-return-codes/
Our software is simply reporting the bank's notification not to honor the payment. We do not play any part in the bank's reasoning for the returned payment, nor do you as the owner. The Tenant must handle the concern with their bank, and they need to provide you with a valid form of payment for their invoice that is still due.
Please let us know if you need further assistance.