Let me route you to the correct support, austin_strings.

When it comes to payments, I'd recommend reaching out to our QuickBooks Payments Support team. This way, our agents there can verify what causes the transaction to be declined.

You can view their contact details through this link: QuickBooks Payments. Just a heads up, our QuickBooks Payments support agents are open every Monday to Friday from 6 AM to 6 PM PST.

I've also added this reference for more information about processing eChecks: Accept ACH payments and eChecks.

I'll be around if ever there's anything that I can help. Stay safe!