I've got some info about the error message and how we can resolve this, @aveabc.

The error "You can try again, or come back later and try connecting then" happens when your bank declines the payment. Thus, I recommend contacting your bank to verify its root cause.

If there's no problem on your bank's end, we can perform some troubleshooting steps to fix this. There are times that the browser is full of frequently accessed page resources, which caused some errors and/or unusual responses. Let's start by accessing your account using a different or a private browser. 

 You can use either of these shortcut keys:

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

If it works successfully, you'd want to clear your regular browser's cache to prevent any unexpected behavior. Also, you can use other compatible browsers in QBO.

If the issue persists, recommend contacting our customer care. This way, they can check your account in a secure space and investigate it further. To do this, please refer to this article: Contact Support. It also contains the support hours on when they're available to assist you.

In addition, you can also accept payments within QuickBooks Online without sending an invoice to them. You can either create a sales receipt or receive payment toward an invoice. Please check this link and choose either option 1 or 2: Process a credit card payment in QuickBooks Online.

Keep me posted if you need more help managing your client's payment in QuickBooks. I'll be happy to assist you always. Have a blissful day.