How can i send mail from asp.net page?Getting error while trying to send email from ASP.net application?

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C#

ASP.NET

mail

In my application I would like to send a mail and I am using the below code,

protected void SendMail()
   {
       // Gmail Address from where you send the mail
       var fromAddress = "xxxxx@gmail.com";
       // any address where the email will be sending
       var toAddress = txtto.Text.ToString();
       //Password of your gmail address
       const string fromPassword = "*****";
       // Passing the values and make a email formate to display
       string subject = "Testing";
       string body = "xxx";

       // smtp settings
       var smtp = new System.Net.Mail.SmtpClient();
       {
           smtp.Host = "smtp.gmail.com"
           smtp.Port = 587;
           smtp.EnableSsl = true;
           smtp.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
           smtp.Credentials = new NetworkCredential(fromAddress, fromPassword);
           smtp.Timeout = 2000000;
       }
       // Passing values to smtp object
       smtp.Send(fromAddress, toAddress, subject, body);
   }
   protected void btnsend_Click(object sender, EventArgs e)
   {
       try
       {
         
           {
               SendMail();
              
           }
       }
       catch (Exception ex)
       {
           Response.Write("Could not send the e-mail - error" +ex.Message);
       }

   }

but I getting an error:
Could not send the e-mail - error: Failure sending mail.

[Edit]Code block added[/Edit]