Send Email using Gmail in C#¶

In previous section, I introduced how to send email over SSL/TLS connection. In this section, I will introduce how to send email using Gmail account in C#.

Sections:

Introduction
Gmail App Password
[C# - Send Email using Gmail Account over Implicit SSL on 465 Port]
[C# - Send Email using Gmail Account over Explicit SSL (TLS) on 25 or 587 Port]
Gmail SMTP OAUTH
TLS 1.2

Introduction¶

Gmail SMTP server address is smtp.gmail.com. It requires implicit SSL or explicit SSL (TLS) connection, and you should use your Gmail email address as the user name for ESMTP authentication.

Server	Port	SSL/TLS
smtp.gmail.com	25, 587	TLS
smtp.gmail.com	465	SSL

Gmail App Password¶

To help keep your account secure, starting May 30, 2022, Google will no longer support the use of third-party apps or devices which ask you to sign in to your Google Account using only your username and password.

Therefore, you should sign in using App Passwords. An App Password is a 16-digit passcode that gives a less secure app or device permission to access your Google Account. App Passwords can only be used with accounts that have 2-Step Verification turned on. You need to use App Password instead of the user password for user authentication.

Another solution is Gmail OAUH, please see Gmail SMTP OAUTH section.

Note

Remarks: All of samples in this section are based on first section: Send email in a simple C# project. To compile and run the following example codes successfully, please click here to learn how to create the test project and add reference of EASendMail to your project.

[C# - Send Email using Gmail Account over Implicit SSL on 465 Port]¶

The following example codes demonstrate how to send email using Gmail account over SSL in C#.

Note

To get the full sample projects, please refer to Samples section.

using System;
using System.Collections.Generic;
using System.Text;
using EASendMail; //add EASendMail namespace
namespace mysendemail
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                SmtpMail oMail = new SmtpMail("TryIt");

                // Your gmail email address
                oMail.From = "gmailid@gmail.com";
                // Set recipient email address
                oMail.To = "support@emailarchitect.net";

                // Set email subject
                oMail.Subject = "test email from gmail account";
                // Set email body
                oMail.TextBody = "this is a test email sent from c# project with gmail.";

                // Gmail SMTP server address
                SmtpServer oServer = new SmtpServer("smtp.gmail.com");

                // Gmail user authentication
                // For example: your email is "gmailid@gmail.com", then the user should be the same
                oServer.User = "gmailid@gmail.com";

                // Create app password in Google account
                // https://support.google.com/accounts/answer/185833?hl=en
                oServer.Password = "your app password";

                // Set 465 port
                oServer.Port = 465;

                // detect SSL/TLS automatically
                oServer.ConnectType = SmtpConnectType.ConnectSSLAuto;

                Console.WriteLine("start to send email over SSL ...");

                SmtpClient oSmtp = new SmtpClient();
                oSmtp.SendMail(oServer, oMail);

                Console.WriteLine("email was sent successfully!");
            }
            catch (Exception ep)
            {
                Console.WriteLine("failed to send email with the following error:");
                Console.WriteLine(ep.Message);
            }
        }
    }
}

[C# - Send Email using Gmail Account over Explicit SSL (TLS) on 25 or 587 Port]¶

The following example codes demonstrate how to send email using Gmail account over TLS in C#.

Note

To get the full sample projects, please refer to Samples section.

using System;
using System.Collections.Generic;
using System.Text;
using EASendMail; //add EASendMail namespace
namespace mysendemail
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                SmtpMail oMail = new SmtpMail("TryIt");

                // Your gmail email address
                oMail.From = "gmailid@gmail.com";
                // Set recipient email address
                oMail.To = "support@emailarchitect.net";

                // Set email subject
                oMail.Subject = "test email from gmail account";
                // Set email body
                oMail.TextBody = "this is a test email sent from c# project with gmail.";

                // Gmail SMTP server address
                SmtpServer oServer = new SmtpServer("smtp.gmail.com");
                // Gmail user authentication
                // For example: your email is "gmailid@gmail.com", then the user should be the same
                oServer.User = "gmailid@gmail.com";

                // Create app password in Google account
                // https://support.google.com/accounts/answer/185833?hl=en
                oServer.Password = "your app password";

                // Set 587 port, if you want to use 25 port, please change 587 5o 25
                oServer.Port = 587;

                // detect SSL/TLS automatically
                oServer.ConnectType = SmtpConnectType.ConnectSSLAuto;

                Console.WriteLine("start to send email over SSL ...");

                SmtpClient oSmtp = new SmtpClient();
                oSmtp.SendMail(oServer, oMail);

                Console.WriteLine("email was sent successfully!");
            }
            catch (Exception ep)
            {
                Console.WriteLine("failed to send email with the following error:");
                Console.WriteLine(ep.Message);
            }
        }
    }
}

Gmail SMTP OAUTH¶

The Gmail IMAP and SMTP servers have been extended to support authorization via the industry-standard OAuth 2.0 protocol. Using OAUTH protocol, user can do authentication by Gmail Web OAuth instead of inputting user and password directly in application.

Google will disable traditional user authentication in the future, switching to Google OAuth is strongly recommended now.

TLS 1.2¶

TLS is the successor of SSL, more and more SMTP servers require TLS 1.2 encryption now.

If your operating system is Windows XP/Vista/Windows 7/Windows 2003/2008/2008 R2/2012/2012 R2, and you got connection error with SSL/TLS connection, you need to enable TLS 1.2 protocol in your operating system like this:

Enable TLS 1.2 on Windows XP/Vista/7/10/Windows 2008/2008 R2/2012

Next Section

At next section I will introduce how to send email using Yahoo account in C#.

Tutorial Index

Send Email using Gmail in C#¶

Introduction¶

Gmail App Password¶

[C# - Send Email using Gmail Account over Implicit SSL on 465 Port]¶

[C# - Send Email using Gmail Account over Explicit SSL (TLS) on 25 or 587 Port]¶

Gmail SMTP OAUTH¶

TLS 1.2¶

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