American Express Online Banking Sync Broken

This isn't something wrong on your end; it's tied to how the bank connection is working with American Express right now.
 

1. Disconnect all American Express accounts from QuickBooks.
2. Assign a unique nickname to each bank account to prevent conflicts.
3. Select the correct provider when reconnecting: choose "American Express" as the primary account holder, or "American Express Delegate" if managing on behalf of someone else.
4. Authorize every account Amex displays during the prompt, including those you don't intend to use in QuickBooks, to prevent error 324.
5. Reconnect only the specific accounts you want to track in QuickBooks.
6. Verify login uniqueness: using a single Amex login for multiple QBO accounts causes conflicts because the bank permits only one QBO connection per login. Contact Amex to separate logins if this applies.

Please refer to this page for further guidance.: Fix bank connection error 324 in QuickBooks Online.

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