Field Validation Error message

Hello all.

I have a field validation rule that is working as expected in production.

=IIf([<pl_Status_ITAG>]='Closed/Won' And PRE('<pl_Status_ITAG>')<>'Closed/Won' And [<bFS_MLA_ITAG>]<>'Y','X',IIf([<pl_Status_ITAG>]='Closed/Won' And PRE('<pl_Status_ITAG>')<>'Closed/Won' And [<stCompany_Brand_ITAG>]is NULL,'X',IIf([<pl_Status_ITAG>]='Closed/Won' And PRE('<pl_Status_ITAG>')<>'Closed/Won' And[<bHas_the_Tax_Exempt_Certificate_ITAG>]<>'Y','X',IIf([<pl_Status_ITAG>]='Closed/Won' And PRE('<pl_Status_ITAG>')<>'Closed/Won' And IfNull([<PrimaryShipToPostalCode>],'Null')='Null','X', IIf([<pl_Status_ITAG>]='Closed/Won' And PRE('<pl_Status_ITAG>')<>'Closed/Won' And ([<bPrimary_Ship_to_Flag_ITAG>]='N' AND [<stSite_Name_ITAG>] is null),'X',[<pl_Status_ITAG>])))))