Connexion POP pour lecture email

Public Function Connection   

       NbMails = 0
        Dim retServer As String
        Try
            ' Initialisation
            co = New TcpClient(Server, ServerPort)

            'ssl
            pop3Stream = New SslStream(co.GetStream(), False)
            pop3Stream.ReadTimeout = 30
            pop3Stream.AuthenticateAsClient(Server)

            ns = co.GetStream()
            sr = New StreamReader(pop3Stream)
            MsgBox(sr.ReadLine)
            Dim sOut As String = "USER " & User & vbCrLf

            ' Envoi du login
            SendStream(sOut)
            retServer = sr.ReadLine

           MsgBox(sr.Readline) 'génère une erreur car sr.Readline=nothing

            RaiseEvent ConnectionStatus(retServer)

            ' Envoi du mot de passe
            sOut = "PASS " & PWord & vbCrLf
            SendStream(sOut)
            retServer = sr.ReadLine
            RaiseEvent ConnectionStatus(retServer)

            If retServer.Substring(0, 4) <> "-ERR" Then
                NbMails = RecupMsgInfo(1)
                RaiseEvent ConnectionStatus("Nombre de mails: " & NbMails.ToString())
                Return True
            Else
                RaiseEvent ConnectionStatus("Identification refusée !")
                Return False
            End If
        Catch ex As Exception
            RaiseEvent ConnectionStatus(ex.ToString())
            Return False
        End Try

End Function

' Envoi des commandes
 Private Sub SendStream(ByVal s As String)
        Dim FluxSortant() As Byte
        FluxSortant = EncodeByte(s)
        Try
            ns.Write(FluxSortant, 0, FluxSortant.Length)
        Catch ex As Exception
            RaiseEvent ConnectionStatus(ex.Message)
        End Try
 End Sub

    ' Encodage des commandes pour POP3
Private Function EncodeByte(ByVal s As String) As Byte()
        Return System.Text.ASCIIEncoding.ASCII.GetBytes(s.ToCharArray())
End Function