Sending email in .NET through Gmail

Be sure to use System.Net.Mail, not the deprecated System.Web.Mail. Doing SSL with System.Web.Mail is a gross mess of hacky extensions.

using System.Net;
using System.Net.Mail;

var fromAddress = new MailAddress("from@gmail.com", "From Name");
var toAddress = new MailAddress("to@example.com", "To Name");
const string fromPassword = "fromPassword";
const string subject = "Subject";
const string body = "Body";

var smtp = new SmtpClient
{
    Host = "smtp.gmail.com",
    Port = 587,
    EnableSsl = true,
    DeliveryMethod = SmtpDeliveryMethod.Network,
    UseDefaultCredentials = false,
    Credentials = new NetworkCredential(fromAddress.Address, fromPassword)
};
using (var message = new MailMessage(fromAddress, toAddress)
{
    Subject = subject,
    Body = body
})
{
    smtp.Send(message);
}

• You can still get user not logged in errors if Google just suddenly decides you have sent too many in the past xx number of minutes. You should always add a trySend, if it errors sleep a while, and then attempt again. - Jason Short
• Interesting note: If you swap 'UseDefaultCredentials = false,' and 'Credentials = ...' it won't authenticate. - Nathan Wheeler
• There are no problems with SPF using this method. Every email client can be configured to do exactly this. You just may get problems if you use your own server (i.e. something else than smtp.gmail.com) with something@gmail.com as sender. Btw: smtp.gmail.com automatically overwrites the sender address if it's not yours. - Meinersbur
• I was having a hard time getting this working even with trying various tweaks. As suggested on a related post, I found that it was actually my antivirus that was preventing emails from being successfully sent. The antivirus in question is McAffee, and its "Access Protection" has a "Antivirus Standard Protection" category that has a "Prevent mass mailing worms from sending email" rule. Tweaking / disabling that rule got this code working for me! - yourbuddypal
• I was getting the 5.5.1 Authentication Required error message until I realized I was testing with an account (my personal one) that had two factor authentication turned on. Once I used an account that didn't have that, it worked fine. I could also have generated a password for my application that I was testing from in my personal acct, but I didn't want to do that. - Nick DeVore

The above answer doesn't work. You have to set DeliveryMethod = SmtpDeliveryMethod.Network or it will come back with a "client was not authenticated" error. Also it's always a good idea to put a timeout.

Revised code:

using System.Net.Mail;
using System.Net;

var fromAddress = new MailAddress("from@gmail.com", "From Name");
var toAddress = new MailAddress("to@yahoo.com", "To Name");
const string fromPassword = "password";
const string subject = "test";
const string body = "Hey now!!";

var smtp = new SmtpClient
{
    Host = "smtp.gmail.com",
    Port = 587,
    EnableSsl = true,
    DeliveryMethod = SmtpDeliveryMethod.Network,
    Credentials = new NetworkCredential(fromAddress.Address, fromPassword),
    Timeout = 20000
};
using (var message = new MailMessage(fromAddress, toAddress)
{
    Subject = subject,
    Body = body
})
{
    smtp.Send(message);
}

• Interesting; it works on my machine (TM). But since this seems plausible, I'll add it to my answer. - Domenic
• Hmm my guess is that SmtpDeliveryMethod.Network is the default, but maybe the default gets changed when running in IIS---was that what you were doing? - Domenic
• I ran it from a desktop app. - Donny V.
• I am using same code in Console application, it's through error "Failure sending mail." - Karthikeyan P
• This answer doesnt work. Please, look at the question stackoverflow.com/questions/34851484/… - user5515846

For the other answers to work "from a server" first Turn On Access for less secure apps in the gmail account.

Looks like recently google changed it's security policy. The top rated answer no longer works, until you change your account settings as described here: https://support.google.com/accounts/answer/6010255?hl=en-GB

As of March 2016, google changed the setting location again!

• This worked for me. And is also concerning. Not sure I want to turn that security off. May need to rethink... - Sully
• From security point of view better to turn on 2-step Verification and then generate and use app password- see How to send an email in .Net according to new security policies? - Michael Freidgeim
• @BCS Software, inmy program, the user insert any email which my program has to use it to send the message throught. So, how I can make the email user able to send the email even if the 2-factor authentication is turned on?? - Alaa'

This is to send email with attachement.. Simple and short..

source: http://coding-issues.blogspot.in/2012/11/sending-email-with-attachments-from-c.html

using System.Net;
using System.Net.Mail;

public void email_send()
{
    MailMessage mail = new MailMessage();
    SmtpClient SmtpServer = new SmtpClient("smtp.gmail.com");
    mail.From = new MailAddress("your mail@gmail.com");
    mail.To.Add("to_mail@gmail.com");
    mail.Subject = "Test Mail - 1";
    mail.Body = "mail with attachment";

    System.Net.Mail.Attachment attachment;
    attachment = new System.Net.Mail.Attachment("c:/textfile.txt");
    mail.Attachments.Add(attachment);

    SmtpServer.Port = 587;
    SmtpServer.Credentials = new System.Net.NetworkCredential("your mail@gmail.com", "your password");
    SmtpServer.EnableSsl = true;

    SmtpServer.Send(mail);

}

Google may block sign in attempts from some apps or devices that do not use modern security standards. Since these apps and devices are easier to break into, blocking them helps keep your account safer.

Some examples of apps that do not support the latest security standards include:

• The Mail app on your iPhone or iPad with iOS 6 or below
  
• The Mail app on your Windows phone preceding the 8.1 release
  
• Some Desktop mail clients like Microsoft Outlook and Mozilla Thunderbird

Therefore, you have to enable Less Secure Sign-In in your google account.

After sign into google account, go to:

https://myaccount.google.com/lesssecureapps
or
https://www.google.com/settings/security/lesssecureapps

In C#, you can use the following code:

using (MailMessage mail = new MailMessage())
{
    mail.From = new MailAddress("email@gmail.com");
    mail.To.Add("somebody@domain.com");
    mail.Subject = "Hello World";
    mail.Body = "<h1>Hello</h1>";
    mail.IsBodyHtml = true;
    mail.Attachments.Add(new Attachment("C:\\file.zip"));

    using (SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587))
    {
        smtp.Credentials = new NetworkCredential("email@gmail.com", "password");
        smtp.EnableSsl = true;
        smtp.Send(mail);
    }
}

Here is my version: "Send Email In C # Using Gmail".

using System;
using System.Net;
using System.Net.Mail;

namespace SendMailViaGmail
{
   class Program
   {
   static void Main(string[] args)
   {

      //Specify senders gmail address
      string SendersAddress = "Sendersaddress@gmail.com";
      //Specify The Address You want to sent Email To(can be any valid email address)
      string ReceiversAddress = "ReceiversAddress@yahoo.com";
      //Specify The password of gmial account u are using to sent mail(pw of sender@gmail.com)
      const string SendersPassword = "Password";
      //Write the subject of ur mail
      const string subject = "Testing";
      //Write the contents of your mail
      const string body = "Hi This Is my Mail From Gmail";

      try
      {
        //we will use Smtp client which allows us to send email using SMTP Protocol
        //i have specified the properties of SmtpClient smtp within{}
        //gmails smtp server name is smtp.gmail.com and port number is 587
        SmtpClient smtp = new SmtpClient
        {
           Host = "smtp.gmail.com",
           Port = 587,
           EnableSsl = true,
           DeliveryMethod = SmtpDeliveryMethod.Network,
           Credentials    = new NetworkCredential(SendersAddress, SendersPassword),
           Timeout = 3000
        };

        //MailMessage represents a mail message
        //it is 4 parameters(From,TO,subject,body)

        MailMessage message = new MailMessage(SendersAddress, ReceiversAddress, subject, body);
        /*WE use smtp sever we specified above to send the message(MailMessage message)*/

        smtp.Send(message);
        Console.WriteLine("Message Sent Successfully");
        Console.ReadKey();
     }

     catch (Exception ex)
     {
        Console.WriteLine(ex.Message);
        Console.ReadKey();
     }
    }
   }
 }

• While your article may in fact answer the question, it would be preferable to include the essential parts of the answer here, and provide the link for reference. Stack Overflow is only as useful as its questions and answers, and if your blog host goes down or your URLs get moved around, this answer becomes useless. Thanks! - sarnold

For me to get it to work, i had to enable my gmail account making it possible for other apps to gain access. This is done with the "enable less secure apps" and also using this link: https://accounts.google.com/b/0/DisplayUnlockCaptcha

I hope this code will work fine. You can have a try.

// Include this.                
using System.Net.Mail;

string fromAddress = "xyz@gmail.com";
string mailPassword = "*****";       // Mail id password from where mail will be sent.
string messageBody = "Write the body of the message here.";


// Create smtp connection.
SmtpClient client = new SmtpClient();
client.Port = 587;//outgoing port for the mail.
client.Host = "smtp.gmail.com";
client.EnableSsl = true;
client.Timeout = 10000;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential(fromAddress, mailPassword);


// Fill the mail form.
var send_mail = new MailMessage();

send_mail.IsBodyHtml = true;
//address from where mail will be sent.
send_mail.From = new MailAddress("from@gmail.com");
//address to which mail will be sent.           
send_mail.To.Add(new MailAddress("to@example.com");
//subject of the mail.
send_mail.Subject = "put any subject here";

send_mail.Body = messageBody;
client.Send(send_mail);

• message send_mail = new MailMessage(); How is this line suppose to work? You can't implicitly convert 'System.Net.Mail.MailMessage' to 'System.Windows.Forms.Message' - Debaprasad

Include this,

using System.Net.Mail;

And then,

MailMessage sendmsg = new MailMessage(SendersAddress, ReceiversAddress, subject, body); 
SmtpClient client = new SmtpClient("smtp.gmail.com");

client.Port = Convert.ToInt16("587");
client.Credentials = new System.Net.NetworkCredential("mail-id@gmail.com","password");
client.EnableSsl = true;

client.Send(sendmsg);

Source : Send email in ASP.NET C#

Below is a sample working code for sending in a mail using C#, in the below example I am using google’s smtp server.

The code is pretty self explanatory, replace email and password with your email and password values.

public void SendEmail(string address, string subject, string message)
{
    string email = "yrshaikh.mail@gmail.com";
    string password = "put-your-GMAIL-password-here";

    var loginInfo = new NetworkCredential(email, password);
    var msg = new MailMessage();
    var smtpClient = new SmtpClient("smtp.gmail.com", 587);

    msg.From = new MailAddress(email);
    msg.To.Add(new MailAddress(address));
    msg.Subject = subject;
    msg.Body = message;
    msg.IsBodyHtml = true;

    smtpClient.EnableSsl = true;
    smtpClient.UseDefaultCredentials = false;
    smtpClient.Credentials = loginInfo;
    smtpClient.Send(msg);
}

• Instead of var ,I have used class name like NetworkCredential,MailMessage and SmtpClient.It work for me. - Jui Test

If you want to send background email, then please do the below

 public void SendEmail(string address, string subject, string message)
 {
 Thread threadSendMails;
 threadSendMails = new Thread(delegate()
    {

      //Place your Code here 

     });
  threadSendMails.IsBackground = true;
  threadSendMails.Start();
}

and add namespace

using System.Threading;

use this way

MailMessage sendmsg = new MailMessage(SendersAddress, ReceiversAddress, subject, body); 
SmtpClient client = new SmtpClient("smtp.gmail.com");

client.Port = Convert.ToInt32("587");
client.EnableSsl = true;
client.Credentials = new System.Net.NetworkCredential("mail-id@gmail.com","MyPassWord");
client.Send(sendmsg);

Don't forget this :

using System.Net;
using System.Net.Mail;

One Tip! Check the sender inbox, maybe you need allow less secure apps. See: https://www.google.com/settings/security/lesssecureapps

Try This,

    private void button1_Click(object sender, EventArgs e)
    {
        try
        {
            MailMessage mail = new MailMessage();
            SmtpClient SmtpServer = new SmtpClient("smtp.gmail.com");

            mail.From = new MailAddress("your_email_address@gmail.com");
            mail.To.Add("to_address");
            mail.Subject = "Test Mail";
            mail.Body = "This is for testing SMTP mail from GMAIL";

            SmtpServer.Port = 587;
            SmtpServer.Credentials = new System.Net.NetworkCredential("username", "password");
            SmtpServer.EnableSsl = true;

            SmtpServer.Send(mail);
            MessageBox.Show("mail Send");
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.ToString());
        }
    }

Changing sender on Gmail / Outlook.com email:

To prevent spoofing - Gmail/Outlook.com won't let you send from an arbitrary user account name.

If you have a limited number of senders you can follow these instructions and then set the From field to this address: Sending mail from a different address

If you are wanting to send from an arbitrary email address (such as a feedback form on website where the user enters their email and you don't want them emailing you directly) about the best you can do is this :

        msg.ReplyToList.Add(new System.Net.Mail.MailAddress(email, friendlyName));

This would let you just hit 'reply' in your email account to reply to the fan of your band on a feedback page, but they wouldn't get your actual email which would likely lead to a tonne of spam.

If you're in a controlled environment this works great, but please note that I've seen some email clients send to the from address even when reply-to is specified (I don't know which).

I had the same issue, but it was resolved by going to gmail's security settings and Allowing Less Secure apps. The Code from Domenic & Donny works, but only if you enabled that setting

If you are signed in (to Google) you can follow this link and toggle "Turn on" for "Access for less secure apps"

using System;
using System.Net;
using System.Net.Mail;

namespace SendMailViaGmail
{
   class Program
   {
   static void Main(string[] args)
   {

      //Specify senders gmail address
      string SendersAddress = "Sendersaddress@gmail.com";
      //Specify The Address You want to sent Email To(can be any valid email address)
      string ReceiversAddress = "ReceiversAddress@yahoo.com";
      //Specify The password of gmial account u are using to sent mail(pw of sender@gmail.com)
      const string SendersPassword = "Password";
      //Write the subject of ur mail
      const string subject = "Testing";
      //Write the contents of your mail
      const string body = "Hi This Is my Mail From Gmail";

      try
      {
        //we will use Smtp client which allows us to send email using SMTP Protocol
        //i have specified the properties of SmtpClient smtp within{}
        //gmails smtp server name is smtp.gmail.com and port number is 587
        SmtpClient smtp = new SmtpClient
        {
           Host = "smtp.gmail.com",
           Port = 587,
           EnableSsl = true,
           DeliveryMethod = SmtpDeliveryMethod.Network,
           Credentials = new NetworkCredential(SendersAddress, SendersPassword),
           Timeout = 3000
        };

        //MailMessage represents a mail message
        //it is 4 parameters(From,TO,subject,body)

        MailMessage message = new MailMessage(SendersAddress, ReceiversAddress, subject, body);
        /*WE use smtp sever we specified above to send the message(MailMessage message)*/

        smtp.Send(message);
        Console.WriteLine("Message Sent Successfully");
        Console.ReadKey();
     }
     catch (Exception ex)
     {
        Console.WriteLine(ex.Message);
        Console.ReadKey();
     }
}
}
}

Here is one method to send mail and getting credentials from web.config:

public static string SendEmail(string To, string Subject, string Msg, bool bodyHtml = false, bool test = false, Stream AttachmentStream = null, string AttachmentType = null, string AttachmentFileName = null)
{
    try
    {
        System.Net.Mail.MailMessage newMsg = new System.Net.Mail.MailMessage(System.Configuration.ConfigurationManager.AppSettings["mailCfg"], To, Subject, Msg);
        newMsg.BodyEncoding = System.Text.Encoding.UTF8;
        newMsg.HeadersEncoding = System.Text.Encoding.UTF8;
        newMsg.SubjectEncoding = System.Text.Encoding.UTF8;

        System.Net.Mail.SmtpClient smtpClient = new System.Net.Mail.SmtpClient();
        if (AttachmentStream != null && AttachmentType != null && AttachmentFileName != null)
        {
            System.Net.Mail.Attachment attachment = new System.Net.Mail.Attachment(AttachmentStream, AttachmentFileName);
            System.Net.Mime.ContentDisposition disposition = attachment.ContentDisposition;
            disposition.FileName = AttachmentFileName;
            disposition.DispositionType = System.Net.Mime.DispositionTypeNames.Attachment;

            newMsg.Attachments.Add(attachment);
        }
        if (test)
        {
            smtpClient.PickupDirectoryLocation = "C:\\TestEmail";
            smtpClient.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.SpecifiedPickupDirectory;
        }
        else
        {
            //smtpClient.EnableSsl = true;
        }

        newMsg.IsBodyHtml = bodyHtml;
        smtpClient.Send(newMsg);
        return SENT_OK;
    }
    catch (Exception ex)
    {

        return "Error: " + ex.Message
             + "<br/><br/>Inner Exception: "
             + ex.InnerException;
    }

}

And the corresponding section in web.config:

<appSettings>
    <add key="mailCfg" value="yourmail@example.com"/>
</appSettings>
<system.net>
  <mailSettings>
    <smtp deliveryMethod="Network" from="yourmail@example.com">
      <network defaultCredentials="false" host="mail.exapmple.com" userName="yourmail@example.com" password="your_password" port="25"/>
    </smtp>
  </mailSettings>
</system.net>

The problem for me was that my password had a blackslash "\" in it, which I copy pasted without realizing it would cause problems.

Try this one

public static bool Send(string receiverEmail, string ReceiverName, string subject, string body)
{
        MailMessage mailMessage = new MailMessage();
        MailAddress mailAddress = new MailAddress("abc@gmail.com", "Sender Name"); // abc@gmail.com = input Sender Email Address 
        mailMessage.From = mailAddress;
        mailAddress = new MailAddress(receiverEmail, ReceiverName);
        mailMessage.To.Add(mailAddress);
        mailMessage.Subject = subject;
        mailMessage.Body = body;
        mailMessage.IsBodyHtml = true;

        SmtpClient mailSender = new SmtpClient("smtp.gmail.com", 587)
        {
            EnableSsl = true,
            UseDefaultCredentials = false,
            DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network,
            Credentials = new NetworkCredential("abc@gmail.com", "pass")   // abc@gmail.com = input sender email address  
                                                                           //pass = sender email password
        };

        try
        {
            mailSender.Send(mailMessage);
            return true;
        }
        catch (SmtpFailedRecipientException ex)
        { }
        catch (SmtpException ex)
        { }
        finally
        {
            mailSender = null;
            mailMessage.Dispose();
        }
        return false;
}

Copying from another answer, the above methods work but gmail always replaces the "from" and "reply to" email with the actual sending gmail account. apparently there is a work around however:

http://karmic-development.blogspot.in/2013/10/send-email-from-aspnet-using-gmail-as.html

"3. In the Accounts Tab, Click on the link "Add another email address you own" then verify it"

Or possibly this

Update 3: Reader Derek Bennett says, "The solution is to go into your gmail Settings:Accounts and "Make default" an account other than your gmail account. This will cause gmail to re-write the From field with whatever the default account's email address is."