How Can I Successfully Send Emails via Gmail's SMTP Server Using C#?

Using C# to Send Email through Gmail SMTP Server

In this article, we address an issue raised by developers encountering difficulties while attempting to send emails through Gmail's SMTP server using C#. We present a solution and demonstrate why alternative approaches may not be functioning.

Problem

Despite following the accepted answer and exploring other suggestions in a previous thread titled "Sending email in .NET through Gmail," users continue to face issues. When employing the code snippet utilizing SmtpDeliveryMethod.Network, an SmtpException arises during Send(message), accompanied by an error message indicating "The SMTP server requires a secure connection or the client was not authenticated."

Why Previous Approaches May Not Work

The issue may stem from the fact that Gmail has been known to modify its email settings. To resolve the problem, users need to ensure that they are utilizing a secure connection and authenticating the client before attempting to send emails.

Solution

The following updated code snippet addresses the issue by explicitly setting up a secure connection and providing user credentials for authentication:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.Mail;
using System.Net;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            var client = new SmtpClient("smtp.gmail.com", 587)
            {
                Credentials = new NetworkCredential("[email protected]", "mypwd"),
                EnableSsl = true
            };
            client.Send("[email protected]", "[email protected]", "test", "testbody");
            Console.WriteLine("Sent");
            Console.ReadLine();
        }
    }
}

Additional Considerations

• In 2021, Google introduced a requirement to enable access for "less secure apps" within Gmail settings. This step is necessary to avoid encountering an authentication error message.
• If the code works for some users but not others, it is recommended to review the specific code implementation and ensure that all necessary settings are correctly configured.

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