Do like this
using System;
using System.Collections.Generic;
using System.Data;
using System.Web.Mail;
using System.Net;
using System.Net.Mail;
using System.IO;
public partial class Support : Page
{
protected void Page_Load(object sender, EventArgs e)
{
string Fullname = txtFullName.Text;
string DepartmentDivision = txtDepartment.Text;
string Piriority = ddlpriority.SelectedItem.Text;
SmtpClient serverobj = new SmtpClient();
serverobj.Timeout = 100;
serverobj.Credentials = new NetworkCredential(ConfigurationManager.AppSettings["Username"].ToString(), ConfigurationManager.AppSettings["UserPass"].ToString());
serverobj.Port = System.Convert.ToInt32(ConfigurationManager.AppSettings["Port"].ToString());
serverobj.Host = ConfigurationManager.AppSettings["HostName"].ToString(); ;
serverobj.EnableSsl = false;
obj = new System.Net.Mail.MailMessage();
obj.From = new MailAddress(txtEmail.Text, "Support Query", System.Text.Encoding.UTF8);
obj.To.Add(ConfigurationManager.AppSettings["Username"]);
obj.Priority = System.Net.Mail.MailPriority.High;
obj.Subject = txtsubject.Text;
obj.Body = " Name:" + Fullname + "," + "\n" + "EmailId:" + txtEmail.Text + "" + "\n" + "DepartMent:" + DepartmentDivision + "" + "\n" + "Piriority:" + Piriority + "" + "\n" + "Subject:" + txtsubject.Text + "" + "\n" + "Description:" + ASPxMemo1.Text + "";
}
}
in web config:
<appSettings>
<add key="HostName" value="gmail.com" />
<add key="Port" value="587" />
<add key="EmailFrom" value="anil@gmail.com" />
<add key="Username" value="anil@gmail.com" />
<add key="UserPass" value="password" />
</appSettings>
<system.net>
<mailSettings>
<smtp from="anil@gmail.com" deliveryMethod="Network">
<network host="anil@gmail.com" defaultCredentials="true" userName="username" password="password" />
</smtp>
</mailSettings>
</system.net>
Try this it will work
Regards,
Anilkumar.D