QuickBooks Error 324 occurs when QuickBooks Online cannot find the account on your bank’s website. This issue typically arises due to changes on the bank’s end, such as the account being closed, renamed, or having altered details. To resolve this error, log in to your bank’s website to verify your account status and ensure all information is accurate. If the account was closed or renamed, update QuickBooks with the new account details. Additionally, ensure that your bank connection is active and the login credentials in QuickBooks match those used for your bank’s website.