error in asp.net code to send email

There is nothing wrong with your code.
Since you are using ASP.NET, can you try adding the following in web.config file

<system.net>
	<defaultproxy>
		<proxy proxyaddress="ip address of proxy server" />
	</defaultproxy>
</system.net>

The error is self descriptive, system unable to access Smtp.gmail.com from your machine.
1. check firewall settings
2. try pinging Smtp.gmail.com from your machine
3. open a command prompt, and type "nslookup www.gmail.com". see if you get response and domain ip
if not then your domain setting

use this code

MailMessage oMsg = new MailMessage();
                oMsg.From = new MailAddress("xxx@gmail.com", "xxx");
                oMsg.To.Add(new MailAddress("yyy@gmail.com", "xxx"));
                oMsg.Subject = "Packet Parsing Problem";
                oMsg.Body = " Problem Occuread test mail";
                oMsg.SubjectEncoding = System.Text.Encoding.UTF8;
                oMsg.BodyEncoding = System.Text.Encoding.UTF8;
                oMsg.IsBodyHtml = false;
                oMsg.Priority = MailPriority.High;
 
                SmtpClient oSmtp = new SmtpClient("smtp.gmail.com", 587);
                oSmtp.DeliveryMethod = SmtpDeliveryMethod.Network;
                oSmtp.EnableSsl = true;
 
                NetworkCredential oCredential = new NetworkCredential("xxx@gmail.com", "123456aA");
                oSmtp.UseDefaultCredentials = false;
                oSmtp.Credentials = oCredential;
                oSmtp.Send(oMsg);

Thanks
--RA

Use System.net namspace. create object for nerworkcredantial with ur gmail username and password.

Hi anoop,
use this code

MailAddress mailfrom = new MailAddress ( "frommail@gmail.com" );
           MailAddress mailto = new MailAddress ( "tomail@gmail.com" );
           MailMessage newmsg = new MailMessage ( mailfrom, mailto );

           newmsg.Subject = "Subject of Email";
           newmsg.Body = "Body(message) of email";

           ////For File Attachment, more file can also be attached

           //Attachment att = new Attachment ( "G:\\code.txt" );
           //newmsg.Attachments.Add ( att );

           SmtpClient smtps = new SmtpClient ( "smtp.gmail.com", 587 );
           smtps.UseDefaultCredentials = false;
           smtps.Credentials = new NetworkCredential ( "mail@gmail.com", "pwd" );
           smtps.EnableSsl = true;
           smtps.Send ( newmsg );

email-sending-in-aspnet[^]

Hey Buddy,

I had created an article on the same:

http://www.c-sharpcorner.com/UploadFile/cd7c2e/send-bulk-mails-using-smtp-configuration-part-2/[^]

You can download the source code available in the Article

try this one once....

protected void btnSubmit_Click1(object sender, EventArgs e)
{
if (txtName.Text != "")
{
if (txtEmail.Text != "")
{
if (txtMessage.Text != "")
{
string result = "Message Sent Successfully..!!";
try
{


string senderID = ConfigurationManager.AppSettings["PFUserName"].ToString();// use sender's email id here..

try
{
MailMessage Msg = new MailMessage();
// Sender e-mail address.
Msg.From = new MailAddress(txtEmail.Text);
// Recipient e-mail address.
Msg.To.Add("usermail");
Msg.Subject = "Feedback Mail";
Msg.Body = "Sender : " + txtEmail.Text + "\n" + "Name : " + txtName.Text + "\n" + "Subject : " + txtSubject.Text + "\n" + "Message:" + txtMessage.Text + "\n";
// your remote SMTP server IP.
SmtpClient smtp = new SmtpClient();
smtp.Host = "smtp.gmail.com";
smtp.Port = 587;
smtp.Credentials = new System.Net.NetworkCredential("usermail", "Password");
smtp.EnableSsl = true;
smtp.Send(Msg);
//ScriptManager.RegisterStartupScript(this.Page, this.GetType(), "ASET", "<script type='text/javascript'>alert('Your Message Has Been Send ');</script>", false);
//CleaContents();
}
catch (Exception ex)
{
//result = "Error sending email.!!!";
result = ex.Message;
}
lbltxt.Text = result;
}
catch (Exception ex)
{
//result = "Error sending email.!!!";
result = ex.Message;
}
}
else
lblmsg.Text = "Please enter your Message";
}
else
lblEmail.Text = "Please enter your Mail Id";
}
else
lblname.Text = "Please enter your Name";


}
}