Thanks for keeping us posted, handyman123.
Allow me to give updates about the Error messages you're getting when trying to connect to Capital One.
I appreciate you for providing us a detailed information about the error codes you're having. I've checked the error code specific for the CC334, but haven't found reported cases similar as yours.
I understand that you've already reached out to us about this matter. Yet, the best thing that we can do is to give our Customer Care a quick call. They can pull up your account in a secure environment and take a closer look and create a new investigation about this issue for you.
Here's how you can reach out to our support: Get help with QuickBooks Online.
We appreciate your patience for this. Let me know if there's anything else you need or if you have other questions when connecting bank accounts. I'll be here to help.