Hello krulls_kitchen,
Based on the description of the error, you are having Error 103. This means that the saved banking credentials in QuickBooks Online don't match with your bank's website.
If this is an existing connection, we can update the banking credentials manually. Here's how:
- In the Banking page, highlight the account that are having a problem.
- Click the Edit option (pencil icon).
- Select Edit sign-in info and enter your new credentials.
- Select Update.
You can use a private window or other supported ones if the error occurs. The private browser uses, but doesn't store cache. Meanwhile, other supported browsers use different batches of cache. You can update the banking credentials again afterwards.
If you have a different error code, you can browse this article and follow the suggested troubleshooting steps.
Let me know how this goes. I'll be right here to help you more.