The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required.

See more:

ASP.NET

sir why this problem occures.
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MailMessage mailMsg = new MailMessage();

mailMsg.From = new MailAddress(txtemail.Text);

mailMsg.To.Add("xxxxxxxxxxxxxx@gmail.com");

mailMsg.IsBodyHtml = true;

mailMsg.Subject = "Enquery Details";

mailMsg.Body = "Enquery Details" + "Name:" + txtname.Text + "
Email - address :" + txtemail.Text + "
Place :" + txtplace.Text + "
Mobile:" + txtmobile.Text + "
Check In:" + txtdatecheckin.Text + "
Check Out:" + txtcheckout.Text + "
Message:" + TextBox2.Text;

SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);

mailMsg.Priority = MailPriority.Normal;

smtp.Credentials = new System.Net.NetworkCredential("xxxxxx@gmail.com", "xxxxxxxxxxxxxxxxxxxxxx");

smtp.Timeout = 25000;

smtp.EnableSsl = true;

smtp.Send(mailMsg);
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this code is working fine in local host but upload to server get error:-
The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1



Authentication Required. Learn more at
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Net.Mail.SmtpException: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at

Source Error:


Line 40: smtp.EnableSsl = true;
Line 41:
Line 42: smtp.Send(mailMsg);
Line 43: }
Line 44: }
sir plz help me thans.