The QuickBooks American Express Not Syncing issue is a situation when QuickBooks accounting software is unable to correctly sync transactions from an American Express credit card. This may happen for a number of reasons, including disconnections between QuickBooks and American Express, inaccurate account settings, or incompatibilities. Verifying account settings, upgrading software, or contacting QuickBooks support at 1-855-856-0042 for help may be necessary to fix the problem.