Unable to send Emails from Remote Server using asp.net & C#? - asp.net

Question

I am able to send emails successfully from LocalHost.
After hosting my website i am unable to send.
The following is the error:
System.Net.Mail.SmtpException: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.0 Must issue a STARTTLS command first. ha10sm40374374pbc.23 - gsmtp
can anyone help me to solve this.
Below is code:
public void SendMail(string ToMail, string subject, string Message)
{
// Gmail Address from where you send the mail
string fromAddress = "mygmailid#gmail.com";
// any address where the email will be sending
//string toAddress = ToMail;
//Password of your gmail address
const string fromPassword = "********";
// Passing the values and make a email formate to display
//string subject = subject;
string body = "\n\n"+Message;
// 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 = 20000;
}
// Passing values to smtp object
smtp.Send(fromAddress, ToMail, subject, body);
}

Answer 1

Google sent a mail with the subjact "Suspicious sign in prevented"
I selected it's me only option.
Then changed the Gmail password and used it in the application .
Now able to send the mails from the production server also...

Answer 2

Try below code:
using (MailMessage mailMessage = new MailMessage())
{
mailMessage.From = new MailAddress(email);
mailMessage.Subject = "YOUR_SUBJECT";
mailMessage.Body = "YOUR_MAIL_BODY";
mailMessage.To.Add(new MailAddress("RECIPIENT_EMAILID"));
SmtpClient smtp = new SmtpClient();
smtp.Host = "smtp.gmail.com";
smtp.Port = 587;
smtp.EnableSsl = true;
System.Net.NetworkCredential NetworkCred = new
System.Net.NetworkCredential();
NetworkCred.UserName = "SENDER_MAIL";
NetworkCred.Password = "SENDER_MAIL_PASSWORD";
smtp.UseDefaultCredentials = true;
smtp.Credentials = NetworkCred;
smtp.Send(mailMessage);
}
After invoking above method GOOGLE or GMAIL will send you one mail regarding security (To allow the less secure app to configure mail) then allow that one.