probleme VBA

bonjour, j'ai une formule qui ne marche pas pour verifier si 2 cellules contiennent une chose

Private Sub Worksheet_Change(ByVal Target As Range)
If Application.WorksheetFunction.CountIf(Range("C6:C11"), "21") + Application.WorksheetFunction.CountIf(Range("C6:C11"), "10") = 2 Then

MsgBox "attention"

If Application.WorksheetFunction.CountIf(Range("C6:C11"), "fp ") + Application.WorksheetFunction.CountIf(Range("C6:C11"), "10") = 2 Then

MsgBox "attention"

End if

End sub