The -81511 error message is a decline error message that is occurring between your bank and QuickBooks based on the information you put into the system when updating billing information. I recommend to look over the information and ensure that it's correct. A dot within the name or address can make a difference.
If all of your credentials are correct, then I suggest clearing your browsing data. This will help QuickBooks load as a fresh page to remove any errors or glitches that may be occurring in your account.
Afterward, if the issue persists, then get in touch with your bank to make sure there's no problem on their side.
Here's a link that can be helpful in this situation: