Invalid Customer ID or LVL_ERROR in QuickBooks Invalid Customer ID or LVL_ERROR occurs when Intuit servers detect an invalid customer ID with Online services like Banking.  This error code is found in the Log files of QuickBooks i.e. Qbwin.log, It is recommended to get this issue resolved by an Intuit certified technical support but we … Continue reading How to fix Invalid customer ID error or Log file (Qbwin.log) LVL_ERROR