Welcome to QuickBooks Community, fun-numbers.
There are few possible reasons why you got this error message. It could be that:
- The Financial Institution (FI) moved your account to a new server.
- The account nickname has changed.
- The FI issued a new account number.
- The bank account closed.
You'll want to manually update or reconnect your account. Click on the Reconnect my account after the error message and follow the steps to update your account with the bank. If you can't see the said option, select the Update button instead to manually update your account in QBO.
For additional reference, you can check this article: How to fix banking error 324 in QuickBooks Online.
Let me know if you have other concerns, I'd be glad to help.
