Error: Unable to cast object of type Microsoft.Exchange.WebServices.Data.EmailMessage to type Microsoft.Office.Interop.Outlook.MailItem in ASP.Net

My aim is to copy yesterday mail items to the external folder in my computer i am getting this error in "mailitem = Item" this line.

below is my code:

Dim service As New ExchangeService(ExchangeVersion.Exchange2010_SP2)
    service.Credentials = New WebCredentials("user", "Password", "domain")
    service.AutodiscoverUrl("acce@pac.com.in")
    Dim pageSize As Integer = 100
    Dim offset As Integer = 0
    Dim view As New ItemView(pageSize, offset)
    Dim returnValue As FindItemsResults(Of Item)
    returnValue = service.FindItems(WellKnownFolderName.Inbox, view)
    Dim subject As String
    Dim receiveDate As Date
    Dim maxDate As Date = getLatestDate()
    For Each Item In returnValue
        receiveDate = Item.DateTimeReceived
        If receiveDate > maxDate Then
            Dim strDirPLE As String
            Dim strDirCust As String
            Dim strSaveName As String
            strDirPLE = "D:\test1\"
            strDirCust = "D:\test2\"
            Dim mailitem As Microsoft.Office.Interop.Outlook.MailItem
            mailitem = Item
            subject = Item.Subject.Replace(":", "")
            subject = Item.Subject.Replace(".", "")
            strSaveName = subject & Format(Now, " ddmmyyyyhhnnss") & ".msg"
             If (mailitem.From.Contains("@pac.com.in")) Then
                If (Item.Subject.Contains("CId") AndAlso Item.Subject.Contains("pId")) Then

                    mailitem.SaveAs(strcon1)
                Else
                    mailitem.SaveAs(strcon2)
                End If
            End If

        End If
        Exit For
    Next
End Sub