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Sending message using MailMessage, working fine in localhost but after uploading on Server giving error as given below.

The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.0 Authentication Required. Learn 
more at

What I have tried:

Using following code and i've also set
Less secure app access: ON in google

using (MailMessage emailMessage = new MailMessage())
                    emailMessage.From = new MailAddress(_mailConfig.Value.FromEmail, _mailConfig.Value.FromName);
                    emailMessage.To.Add(new MailAddress(to));
                    emailMessage.Subject = subject;
                    emailMessage.Body = emailBody;
                    emailMessage.IsBodyHtml = true;
                    emailMessage.BodyEncoding = Encoding.UTF8;
                    emailMessage.Priority = MailPriority.Normal;
                    using (SmtpClient MailClient = new SmtpClient("", 587))
                        MailClient.UseDefaultCredentials = false;
                        MailClient.EnableSsl = true;                        
                        MailClient.Credentials = new System.Net.NetworkCredential("", "password");
Updated 20-Sep-21 19:54pm

1 solution

Try to turn Off 2-Step Verification in Gmail.
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