sinon dans la macro tu remplaces la macro par celle-ci :
Private Sub Worksheet_Change(ByVal Target As Range)
Dim cellule As Range
Application.EnableEvents = False
For Each cellule In Sheets(1).Range("A1:A400")
cellule = DateSerial(Year(cellule), Month(cellule), Day(cellule))
If cellule = Target Then
Sheets(1).Select
Sheets(1).Cells(cellule.Row, cellule.Column).Select
Application.EnableEvents = True: Exit Sub
End If
Next cellule
Application.EnableEvents = True
'MsgBox ("La date recherchée est inexistante")
End Sub