Welcome back to our forums, @fun-numbers,
I want to ensure you’re able to connect your bank account error-free in QuickBooks Online.
Typically, the steps provided by my peers should work specifically for the error you're getting. Since the recommended troubleshooting did not work for you, I recommend contacting our QBO Support Team for further investigation. There they can perform a screen-sharing session with you, to trace where the issue is coming from and provide you a fix.
To contact us, follow the steps below:
That should connect you to our live support agents, @fun-numbers.
The Community always has your back and I'm just a reply away if you should have any questions. Have a great day!