Thanks for reaching out to the Community, jrdwllmn.
Let's make sure you can connect your bank into QuickBooks Desktop.
It's possible that your bank requires an extra layer of security that does not allow QuickBooks Desktop to automatically download banking transactions. In some cases, your bank login credentials contain an ever-changing code that's required to access the account and only you can get the code.
You'll want to contact your financial institution and ask on how to obtain the 5 digit PIN.