I'm sorry, but I am getting an invalid use of Null error, with the line in bold highlighted. Thank you.
Private Sub Form_BeforeUpdate(Cancel As Integer)
Me.[Due_Date] = GetBusinessDay([Date_Received], IIf([Test] = "LR", 4, IIf([Test] = "HR", 5, IIf([Test] = "STR", 2, IIf([Test] = "MOLDX"...