Hello there, info-globalexpor. You've come to the right place. I'll ensure you can link your bank account to QuickBooks Online.
We can perform the following steps to fix the error. But, before we proceed, let me share with you the possible reasons why you're getting the error code 324. It may be because of the following:
Your bank or credit card company changed the account or moved it to a new server.
You changed the account name or other info on your bank or credit card company's website.
Your bank or credit card company issued a new account or credit card.