msgbox if todays date is past date in cell

Hey,

When opening a workbook, I want a msgbox to pop up, if todays date is past the date in date in cell c4.
I tried the formula beneath, but it gives me the msgbox nomatter if the condition is met or not.
Thanks in advance for your help and effort.

Private Sub Workbook_Open
With Sheets("Main")
If Range("c4") < Date Then
MsgBox "Workbook has expired", vbOKOnly
Else
Exit Sub
End If
End With

End Sub