Client sees the following when paying my invoice via credit card - Error - Payment wasn’t successful. Try again or contact seller. All fine on his bank end. Any fixes?

Hello there. Allow me to route you to the appropriate support personnel who can handle the online payment issue.

It's relevant to have streamlined payment processes in QuickBooks Online. I recommend reaching out to your online payment service provider for guidance on addressing the specific error message you have encountered.

Here's how to contact them: 

1. Navigate to the QuickBooks App Store link: https://quickbooks.intuit.com/app/apps/home/en-gb/.
2. Locate your online payment provider in the search field.
3. Once found, click on it and locate the Contact Support information at the right side of the page. 

You can also personalise and enhance your sales documents by customising and including specific information, resulting in tailored and professional-looking invoices, estimates, and sales receipts.

Revisit this conversation and comment below if you need additional assistance with any invoice-related tasks. I'm here to assist you at every step of the way and will ensure a prompt response to your queries.