Hello there, @clmatthes.

I've checked here the investigation about the error you're getting when sending an invoice. I’d like you to know that this has been raised to our engineers to understand why this behavior is happening.

Since you already contacted our technical support team, then that means you've already been added to the list of our affected users. You'll receive an email notification as soon as there's an update on this investigation.

In the meantime, you can manually receive or record an invoice payment in your QuickBooks Desktop. Also, you can contact merchant services to process credit card payments.

If you have any other questions, please leave a comment below. I’ll be glad to help. Take care and keep safe!