Have done everything related to error (324). nothing works and have not changed anything with my bank.
This error can occur if QuickBooks is unable to verify your bank's website. There are two ways to ways to get rid of this error. You can either reconnect or update the connected account manually, or connect a new one.
Let's try the first solution which is reconnecting or updating your account manually. Let me show you how:
Select Reconnectmyaccount after the error message.
Choose the updated account with your bank.
If the Reconnectmyaccount link is not available, click the the Update button in the Banking page.
Enter the Multi-Factor Authentication (MFA) credentials.