I made an invoice with back ACH as an acceptable form of payment. My customer informed me the they received an error after validating their banking information.

Hi there, christopher. 

To get started, may I know if your customer has encountered a specific error? A screenshot would be greatly appreciated. I'll wait for your response on this. 

In the meantime, we can ask your customer to perform basic troubleshooting steps to identify if it is a browser-related issue. 

The browser's cache saves files on the computer that enable websites to download faster on your next visit. However, it can also get outdated over time, leading to problems in accessing websites. We can open a QuickBooks Online (QBO) account on an incognito window. Doing so will prevent the browser history from being saved.      

Please refer to the following keyboard shortcuts based on your browser type:

• Google Chrome: Ctrl + Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Microsoft Edge: Ctrl + Shift + P
• Safari: Command + Shift + N

If the private browsing session works, clear the browser's cache so the system can restart. This task is also possible in other supported, up-to-date browsers. Clearing the cache will reboot the system, allowing you to work with a clean slate. 

Regarding your concern about having the option to look if your customers are having issues when making their payments, we can ensure that the ACH mode of payment has been turned on when we process customer remittances. This way, we can guarantee we've selected the appropriate methods for our customer's deposits.    

In addition, refer to this article to learn how to void or refund payments you process through QBO: Void or refund customer payments in QuickBooks Online. 

I'm still all ears if you need further assistance managing your customer's ACH payments. Drop your reply below, and I'll be here to land a hand.