Email sending error with c# and Godaddy server [duplicate]

Answer 1

This has been my approach that worked. I will set up username and password in the web config.

 MailMessage mailMessage = new MailMessage();
 mailMessage.From = new MailAddress("mail@gmail.com", "");
 mailMessage.To.Add(userEmailAddress);
 mailMessage.Subject = subject;
 mailMessage.Body = "";
 mailMessage.IsBodyHtml = true;
 SmtpClient mailSender = new SmtpClient(ConfigurationManager.AppSettings["smtpconn"]);
await mailSender.SendMailAsync(mailMessage);

web config

  <appSetting>
   <add key="smtpconn" value="smtp.gmail.com" />
 </appSettings>
 <system.net>
<mailSettings>
  <smtp from="mail@gmail.com">
    <network host="smtp.gmail.com" port="587" userName="un" password="pw" defaultCredentials="false"/>
  </smtp>
</mailSettings>
</system.net>

Answer 2

I solved, I hope that this aswer helps somebody, this the code is here:

 public ResponseDto sendEmail(EmailDto emailDto) {
        try
        {
            MailMessage message = new MailMessage();
            SmtpClient client = new SmtpClient();
            message.From = new MailAddress("mail@gmail.com");
           message.Subject = "have a new mail";
        message.Body = "info: \n "
            + "name: " + emailDto.Name 
            + "\mail: "+ emailDto.Email + "\nMessage: " +
            emailDto.Message;
            message.To.Add("mail@hotmail.com");
             client.EnableSsl = false;
             client.UseDefaultCredentials = false;
             client.Port = 25;
             client.Host = "relay-hosting.secureserver.net";
             client.Send(message);

        }
        catch (Exception e) {
            return new ResponseDto
            {
                message = e.ToString()
              ,
                Success = false
            };
        }

        return new ResponseDto
        {
            message = "success",
            Success = true
        };

    }

the problem was that other relay/smtp servers will not work from our hosting. and i don't need specify the password. and i change the port and the host, this is the link that help me

https://au.godaddy.com/community/Developer-Cloud-Portal/Unable-to-send-email-from-C-net-application-from-website/td-p/2394