Public Sub InviaMail()
        Dim richiedeAutenticazione As Boolean = True
        Dim richiedeConnessioneProtetta As Boolean = True
        Dim smtpHost As String = “smtp.tiscali.it”
        Dim smtpPort As Integer = 465 '25 default, 465 or 587 for what your provider wants..
        Dim username As String = TextBox2.Text
        Dim password As String = TextBox3.Text
        Dim allegato As String = “c:\allegato.docx”
        Dim EmailMittente As String = TextBox1.Text
        Dim NomeMittente As String = “Giorgio”
        Dim Oggetto As String = TextBox4.Text
        Dim Corpomail As String = TextBox6.Text
        Dim Destinatario As String = TextBox5.Text
        Dim MailConfermaLettura As Boolean = True
        Dim MailConfermaRecapito As Boolean = True
        Dim invioAsincrono As Boolean = True

        Dim smtp As New SmtpClient(“smtp.tiscali.it”)
        'smtp = New SmtpClient

        Dim mail As New MailMessage
        'mail = New MailMessage

        Try

            If richiedeAutenticazione Then
                smtp.UseDefaultCredentials = False
                smtp.Credentials = New Net.NetworkCredential(username, password)
            Else
                smtp.UseDefaultCredentials = True
                smtp.Credentials = Net.CredentialCache.DefaultNetworkCredentials
            End If
            smtp.EnableSsl = If(richiedeConnessioneProtetta, True, False)
            smtp.Host = smtpHost
            smtp.Port = smtpPort

            If String.IsNullOrEmpty(allegato) = False And IO.File.Exists(allegato) Then
                mail.Attachments.Add(New Attachment(allegato))
            End If

            'INDIRIZZI
            'mittente
            mail.From = New MailAddress(EmailMittente, NomeMittente)
            mail.Sender = New Net.Mail.MailAddress(EmailMittente, NomeMittente)
            'destinatari
            mail.To.Add(New Net.Mail.MailAddress(Destinatario, “giorgio Scintu”))
                       
            mail.ReplyToList.Add(New Net.Mail.MailAddress(EmailMittente, NomeMittente))

            mail.Subject = Oggetto
            mail.SubjectEncoding = System.Text.Encoding.UTF8

            mail.Body = Corpomail
            mail.BodyEncoding = System.Text.Encoding.UTF8
            mail.IsBodyHtml = True

            'CONFERMA LETTURA
            If MailConfermaLettura = True Then
                mail.Headers.Add(“Disposition-Notification-To”, EmailMittente)
            End If

            'CONFERMA RECAPITO
            If MailConfermaRecapito = True Then
                mail.Headers.Add(“Return-Receipt-To”, EmailMittente)
                mail.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure Or DeliveryNotificationOptions.OnSuccess
            End If

            mail.Priority = Net.Mail.MailPriority.High

          
                smtp.Send(mail)
                
    End Sub

Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
        Dim MailServerName As String = “smtp.tiscali.it”
        Dim EmailMittente As String = TextBox1.Text
        Dim Oggetto As String = TextBox4.Text
        Dim Corpomail As String = TextBox6.Text
        Dim Destinatario As String = TextBox5.Text

        Dim Message As System.Net.Mail.MailMessage = New System.Net.Mail.MailMessage(EmailMittente, Destinatario, Oggetto, Corpomail)

        Dim MailClient As SmtpClient = New System.Net.Mail.SmtpClient With {
            .Host = MailServerName
        }

        'MailClient.UseDefaultCredentials = True
        MailClient.Send(Message)
        Message.Dispose()

        If Err.Number = 0 Then
            MsgBox(“Richiesta Inviata”, MsgBoxStyle.Information, “Attenzione”)
        Else
            MsgBox(Err.Description, MsgBoxStyle.Exclamation, “Attenzione”)
        End If
    End Sub