=IF(OR([Task Name]12 = "", "", [Due Date]12 < TODAY(), IF(AND(Status12 = "Complete", [Completed date]12 <= [Due Date]12, ISDATE([Completed date]12)), "PASS", "FAIL")))

This is being returned as 'Missing or Invalid Parameters'. (this formula is in Smartsheet rather than Excel hence the different cell references). Please help.

IF OR Error.xlsx