This is my code to send email using GMAIL and VB.NET:
        Try
            Dim SmtpServer As New SmtpClient()
            SmtpServer.Credentials = New Net.NetworkCredential("mygmailid@gmail.com", "mypassword")
            SmtpServer.Port = 587
            SmtpServer.Host = "smtp.gmail.com"
            SmtpServer.EnableSsl = True
            mail = New MailMessage()
            mail.From = New MailAddress("mygmailid@gmail.com", "Asked for help", System.Text.Encoding.UTF8)
            Mail.To.Add("sendtoemail@id")
            Mail.Subject = "A help query has been raised"
            mail.Body = frm_dashboard.user_data_fetch.Item(1, 0).Value.ToString + " " + ask_for_help.txt_message_ask_help.Text
            SmtpServer.Send(Mail)
            MessageBox.Show("Mail sent")
        Catch ex As Exception
            MsgBox(ex.ToString())
            MessageBox.Show("Oops something went wrong.")
        End Try
But this shows me this error:-

 
    