Try entering the logon information again. Be sure that the Caps Lock key on your keyboard is turned off and there are no typos.
Be sure all information is entered exactly as the financial institution sent it to you (except your password, if you have changed it).
Capital letters, spaces, dashes, periods, and other symbols should be used where needed (and only where needed), with no extra ones.
If the Account Number or Routing Number have dashes, try removing them.
Make sure the Account Type shows how your financial institution classifies the account, not the QuickBooks account type.
Check that the logon information you have is for this account at your financial institution, not something else.
For example, you usually need different logon information for QuickBooks than for the financial institution's Web site.
Contact your financial institution to confirm that your online service is active.