Private Sub SendMail()
        Dim fromAddress As New MailAddress("from@mail.com", "Support")
        Dim toAddress As New MailAddress(txtEmail.Text, "User")
        Dim msg As New MailMessage(fromAddress, toAddress)

        msg.Body = My.Application.Info.DirectoryPath + "\support\mailtemplate.html"
        msg.Subject = "Support Ticket"
        msg.IsBodyHtml = True

        Dim mailSender As New System.Net.Mail.SmtpClient()
        mailSender.Host = "mail.myserver.com"
        mailSender.Port = 587
        Try
            mailSender.Send(msg)
            MsgBox("Message sent")
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
End Sub

mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", "1") 'basic authentication
   mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusername", "my_username_here") 'set your username here
   mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword", "super_secret") 'set your password here

Sub Authenticate()
        'create the mail message
        Dim mail As New Net.Mail.MailMessage()

        'set the addresses
        mail.From = New Net.Mail.MailAddress("me@mycompany.com")
        mail.To.Add("you@yourcompany.com")

        'set the content
        mail.Subject = "This is an email"
        mail.Body = "this is the body content of the email."

        'send the message
        Dim smtp As New Net.Mail.SmtpClient("127.0.0.1")

        'to authenticate we set the username and password properites on the SmtpClient
        smtp.Credentials = New Net.NetworkCredential("username", "secret")
        smtp.Send(mail)
    End Sub 'Authenticate