Can't send email on production server.

Describe the bug I tested on local server and used gmail smtp.gmail.com OR company email, it’s worked email send.

But when i release production to customer web server, Email not send and don’t have any error exception.

1) How i can check some service on customer web server are block send email ? 2) I can check the status of the result when send email (complete / failed) ?

Sample on code:

using (var client = new MailKit.Net.Smtp.SmtpClient())
            {
                await client.ConnectAsync(sSmtp, nPort, false);

                // Note: since we don't have an OAuth2 token, disable
                // the XOAUTH2 authentication mechanism.
                client.AuthenticationMechanisms.Remove("XOAUTH2");
                client.AuthenticationMechanisms.Remove("CRAM-MD5");
                client.AuthenticationMechanisms.Remove("DIGEST-MD5");
                await client.AuthenticateAsync(sTemplateEmailEmailFrom, sAuthenPassword);

                try
                {
                    client.Send(message);
                    System.IO.File.WriteAllText("C:\\Temp\\NoError.txt","Send");
                }
                catch (SmtpCommandException ex)
                {
                    Console.WriteLine("Error sending message: {0}", ex.Message);
                    Console.WriteLine("\tStatusCode: {0}", ex.StatusCode);

                    switch (ex.ErrorCode)
                    {
                        case SmtpErrorCode.RecipientNotAccepted:
                            Console.WriteLine("\tRecipient not accepted: {0}", ex.Mailbox);
                            break;
                        case SmtpErrorCode.SenderNotAccepted:
                            Console.WriteLine("\tSender not accepted: {0}", ex.Mailbox);
                            break;

                        case SmtpErrorCode.MessageNotAccepted:
                            Console.WriteLine("\tMessage not accepted.");
                            break;
                    }
                }
                catch (SmtpProtocolException ex)
                {
                    Console.WriteLine("Protocol error while sending message: {0}", ex.Message);
                }
                client.Disconnect(true);
                System.IO.File.WriteAllText("C:\\Temp\\DiscountTrue.txt", "DiscountTrue");
            }
        }

Screenshots I checked on telnet on customer web server

Other information on server:

• OS: Windows Server 2008 R2 Standard SP1

[jstedfast]

Don’t use smtp.gmail.com if you don’t know how to get it working.

GMail blocks you from sending mail unless it recognizes your IP address from a previous login via a web browser.

I don’t know all of the details so I can’t help you. You’ll have to do some google searches and figure it out.

[skashif18]

for me also it’s not working on the production server, I am using my company mail, and the strange thing is there is no error or exception coming.