QuickBooks Error 3120: How to Correct Account Mapping Issues
QuickBooks Error 3120 indicates mismatched account or customer references during sync operations. This error may occur if accounts were renamed or deleted after integration setup. To resolve it, remap income, expense, and payment accounts correctly. Also, verify customer names for consistency between both applications. Running a data rebuild in QuickBooks Desktop can repair minor file issues and improve overall synchronization performance with fewer mapping conflicts.