Msg box response is ignored

Hello,

I am trying to achieve a response from a msgbox which will either continue with the sub or exit. I think my code is right but it doesn't seem to work and just carrys on regardless. Any help would be appreciated.

Private Sub CommandButton1_Click()

Dim MSG1 As Integer

MSG1 = MsgBox("Send Scaffold to destruct?", vbCritical)

If MSG1 = vbCancel Then

Exit Sub

Else
 
Worksheets("sheet2").Activate

ActiveSheet.Range("b4").Select

Do

If IsEmpty(ActiveCell) = False Then

    ActiveCell.Offset(1, 0).Select
   
End If

Loop Until IsEmpty(ActiveCell) = True
    
    
    
    Worksheets("sheet1").Range("A4:h4").Copy
    
    Worksheets("sheet2").Paste Destination:=ActiveCell.Offset(0, -1)
          
    Worksheets("sheet1").Activate
    
    Worksheets("Sheet1").Rows(4).Delete

End If
   
End Sub