Develop Reference

A first chance exception of type 'System.InvalidOperationException' occurred in System.dll [duplicate]

I can't understand why this code is not working. I get an error saying property can not be assigned
MailMessage mail = new MailMessage();
SmtpClient client = new SmtpClient();
client.Port = 25;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Host = "smtp.gmail.com";
mail.To = "user#hotmail.com"; // <-- this one
mail.From = "you#yourcompany.example";
mail.Subject = "this is a test email.";
mail.Body = "this is my test email body";
client.Send(mail);

mail.To and mail.From are readonly. Move them to the constructor.
using System.Net.Mail;
...
MailMessage mail = new MailMessage("you#yourcompany.example", "user#hotmail.com");
SmtpClient client = new SmtpClient();
client.Port = 25;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Host = "smtp.gmail.com";
mail.Subject = "this is a test email.";
mail.Body = "this is my test email body";
client.Send(mail);

This :
mail.To = "user#hotmail.com";
Should be:
mail.To.Add(new MailAddress("user#hotmail.com"));

Finally got working :)
using System.Net.Mail;
using System.Text;
...
// Command line argument must the the SMTP host.
SmtpClient client = new SmtpClient();
client.Port = 587;
client.Host = "smtp.gmail.com";
client.EnableSsl = true;
client.Timeout = 10000;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential("user#gmail.com","password");
MailMessage mm = new MailMessage("donotreply#domain.example", "sendtomyemail#domain.example", "test", "test");
mm.BodyEncoding = UTF8Encoding.UTF8;
mm.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure;
client.Send(mm);
sorry about poor spelling before

public static void SendMail(MailMessage Message)
{
SmtpClient client = new SmtpClient();
client.Host = "smtp.googlemail.com";
client.Port = 587;
client.UseDefaultCredentials = false;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.EnableSsl = true;
client.Credentials = new NetworkCredential("myemail#gmail.com", "password");
client.Send(Message);
}

This is how it works for me. Hope you find it useful
MailMessage objeto_mail = new MailMessage();
SmtpClient client = new SmtpClient();
client.Port = 25;
client.Host = "smtp.internal.mycompany.com";
client.Timeout = 10000;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential("user", "Password");
objeto_mail.From = new MailAddress("from#server.com");
objeto_mail.To.Add(new MailAddress("to#server.com"));
objeto_mail.Subject = "Password Recover";
objeto_mail.Body = "Message";
client.Send(objeto_mail);

First go to https://myaccount.google.com/lesssecureapps and make Allow less secure apps true.
Then use the below code. This below code will work only if your from email address is from gmail.
static void SendEmail()
{
string mailBodyhtml =
"<p>some text here</p>";
var msg = new MailMessage("from#gmail.com", "to1#gmail.com", "Hello", mailBodyhtml);
msg.To.Add("to2#gmail.com");
msg.IsBodyHtml = true;
var smtpClient = new SmtpClient("smtp.gmail.com", 587); //**if your from email address is "from#hotmail.com" then host should be "smtp.hotmail.com"**
smtpClient.UseDefaultCredentials = true;
smtpClient.Credentials = new NetworkCredential("from#gmail.com", "password");
smtpClient.EnableSsl = true;
smtpClient.Send(msg);
Console.WriteLine("Email Sent Successfully");
}

If you want to have your email and password not appear in your code and want your company email client server to use your windows credentials use below.
client.Credentials = CredentialCache.DefaultNetworkCredentials;
Source

This just worked for me as of March 2017.
Started with solution from above "Finally got working :)" which didn't work at first.
SmtpClient client = new SmtpClient();
client.Port = 587;
client.Host = "smtp.gmail.com";
client.EnableSsl = true;
client.Timeout = 10000;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential("<me>#gmail.com", "<my pw>");
MailMessage mm = new MailMessage(from_addr_text, to_addr_text, msg_subject, msg_body);
mm.BodyEncoding = UTF8Encoding.UTF8;
mm.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure;
client.Send(mm);

This answer features:
Using 'using' whenever possible (IDisposable interfaces)
Using Object initializers
Async Programming
Extract SmtpConfig to external class (adjust it to your needs)
Here's the extracted code:
public async Task SendAsync(string subject, string body, string to)
{
using (var message = new MailMessage(smtpConfig.FromAddress, to)
{
Subject = subject,
Body = body,
IsBodyHtml = true
})
{
using (var client = new SmtpClient()
{
Port = smtpConfig.Port,
DeliveryMethod = SmtpDeliveryMethod.Network,
UseDefaultCredentials = false,
Host = smtpConfig.Host,
Credentials = new NetworkCredential(smtpConfig.User, smtpConfig.Password),
})
{
await client.SendMailAsync(message);
}
}
}
Class SmtpConfig:
public class SmtpConfig
{
public string Host { get; set; }
public string User { get; set; }
public string Password { get; set; }
public int Port { get; set; }
public string FromAddress { get; set; }
}

MailMessage mm = new MailMessage(txtEmail.Text, txtTo.Text);
mm.Subject = txtSubject.Text;
mm.Body = txtBody.Text;
if (fuAttachment.HasFile)//file upload select or not
{
string FileName = Path.GetFileName(fuAttachment.PostedFile.FileName);
mm.Attachments.Add(new Attachment(fuAttachment.PostedFile.InputStream, FileName));
}
mm.IsBodyHtml = false;
SmtpClient smtp = new SmtpClient();
smtp.Host = "smtp.gmail.com";
smtp.EnableSsl = true;
NetworkCredential NetworkCred = new NetworkCredential(txtEmail.Text, txtPassword.Text);
smtp.UseDefaultCredentials = true;
smtp.Credentials = NetworkCred;
smtp.Port = 587;
smtp.Send(mm);
Response.write("Send Mail");
View Video:
https://www.youtube.com/watch?v=bUUNv-19QAI

smtp.Host = "smtp.gmail.com"; // the host name
smtp.Port = 587; //port number
smtp.EnableSsl = true; //whether your smtp server requires SSL
smtp.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
smtp.Credentials = new NetworkCredential(fromAddress, fromPassword);
smtp.Timeout = 20000;
Go through this article for more details

Just need to try this:
string smtpAddress = "smtp.gmail.com";
int portNumber = 587;
bool enableSSL = true;
string emailFrom = "companyemail";
string password = "password";
string emailTo = "Your email";
string subject = "Hello!";
string body = "Hello, Mr.";
MailMessage mail = new MailMessage();
mail.From = new MailAddress(emailFrom);
mail.To.Add(emailTo);
mail.Subject = subject;
mail.Body = body;
mail.IsBodyHtml = true;
using (SmtpClient smtp = new SmtpClient(smtpAddress, portNumber))
{
smtp.Credentials = new NetworkCredential(emailFrom, password);
smtp.EnableSsl = enableSSL;
smtp.Send(mail);
}

MailKit is an Open Source cross-platform .NET mail-client library that is based on MimeKit and optimized for mobile devices.
It has more and advance features better than System.Net.Mail
Microsoft TNEF support via MimeKit.
Download nuget package from here.
See this example you can send mail
MimeMessage mailMessage = new MimeMessage();
mailMessage.From.Add(new MailboxAddress(senderName, sender#address.com));
mailMessage.Sender = new MailboxAddress(senderName, sender#address.com);
mailMessage.To.Add(new MailboxAddress(emailid, emailid));
mailMessage.Subject = subject;
mailMessage.ReplyTo.Add(new MailboxAddress(replyToAddress));
mailMessage.Subject = subject;
var builder = new BodyBuilder();
builder.TextBody = "Hello There";
try
{
using (var smtpClient = new SmtpClient())
{
smtpClient.Connect("HostName", "Port", MailKit.Security.SecureSocketOptions.None);
smtpClient.Authenticate("user#name.com", "password");
smtpClient.Send(mailMessage);
Console.WriteLine("Success");
}
}
catch (SmtpCommandException ex)
{
Console.WriteLine(ex.ToString());
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}

Initialize the MailMessage with sender and reciever's email addresses. It should be something like
string from = "codeforwin#gmail.com"; //Senders email
string to = "reciever#gmail.com"; //Receiver's email
MailMessage msg = new MailMessage(from, to);
Read the full code snippet of how to send emails in c#

this would work too..
string your_id = "your_id#gmail.com";
string your_password = "password";
try
{
SmtpClient client = new SmtpClient
{
Host = "smtp.gmail.com",
Port = 587,
EnableSsl = true,
DeliveryMethod = SmtpDeliveryMethod.Network,
Credentials = new System.Net.NetworkCredential(your_id, your_password),
Timeout = 10000,
};
MailMessage mm = new MailMessage(your_iD, "recepient#gmail.com", "subject", "body");
client.Send(mm);
Console.WriteLine("Email Sent");
}
catch (Exception e)
{
Console.WriteLine("Could not end email\n\n"+e.ToString());
}

//Hope you find it useful, it contain too many things
string smtpAddress = "smtp.xyz.com";
int portNumber = 587;
bool enableSSL = true;
string m_userName = "support#xyz.com";
string m_UserpassWord = "56436578";
public void SendEmail(Customer _customers)
{
string emailID = gghdgfh#gmail.com;
string userName = DemoUser;
string emailFrom = "qwerty#gmail.com";
string password = "qwerty";
string emailTo = emailID;
// Here you can put subject of the mail
string subject = "Registration";
// Body of the mail
string body = "<div style='border: medium solid grey; width: 500px; height: 266px;font-family: arial,sans-serif; font-size: 17px;'>";
body += "<h3 style='background-color: blueviolet; margin-top:0px;'>Aspen Reporting Tool</h3>";
body += "<br />";
body += "Dear " + userName + ",";
body += "<br />";
body += "<p>";
body += "Thank you for registering </p>";
body += "<p><a href='"+ sURL +"'>Click Here</a>To finalize the registration process</p>";
body += " <br />";
body += "Thanks,";
body += "<br />";
body += "<b>The Team</b>";
body += "</div>";
// this is done using using System.Net.Mail; & using System.Net;
using (MailMessage mail = new MailMessage())
{
mail.From = new MailAddress(emailFrom);
mail.To.Add(emailTo);
mail.Subject = subject;
mail.Body = body;
mail.IsBodyHtml = true;
// Can set to false, if you are sending pure text.
using (SmtpClient smtp = new SmtpClient(smtpAddress, portNumber))
{
smtp.Credentials = new NetworkCredential(emailFrom, password);
smtp.EnableSsl = enableSSL;
smtp.Send(mail);
}
}
}

send email by smtp
public void EmailSend(string subject, string host, string from, string to, string body, int port, string username, string password, bool enableSsl)
{
try
{
MailMessage mail = new MailMessage();
SmtpClient smtpServer = new SmtpClient(host);
mail.Subject = subject;
mail.From = new MailAddress(from);
mail.To.Add(to);
mail.Body = body;
smtpServer.Port = port;
smtpServer.Credentials = new NetworkCredential(username, password);
smtpServer.EnableSsl = enableSsl;
smtpServer.Send(mail);
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}

Why am I getting a connection timed out when trying to send an email through a CS program?

Firewall: Turned OFF. I am getting a connection timed out error. The email and password are verified.
The exception is: System.Net.Mail.SmtpException : The operation has timed out.
My code
string filename = #"C:\emailsample.htm";
string mailbody = System.IO.File.ReadAllText(filename);
mailbody = mailbody.Replace("##NAME##", firstname.Text);
string to = emailid.Text;
string from = "xxx.abc45#gmail.com";
MailMessage message = new MailMessage(from, to);
message.Subject = "Auto Generated Mail";
message.Body = mailbody;
message.BodyEncoding = Encoding.UTF8;
message.IsBodyHtml = true;
SmtpClient client = new SmtpClient("smtp.gmail.com", 465);
System.Net.NetworkCredential basic = new System.Net.NetworkCredential(from, "Password");
client.EnableSsl = true;
client.Timeout = 20000;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Credentials = basic;
try
{
client.Send(message);
}
catch (Exception ex)
{
System.Windows.MessageBox.Show(ex.ToString());
return;
}

Try modifying the Port to 587.
Also verify if the From email is correct.
SmtpClient client = new SmtpClient();
client.Port = 587;
client.Host = "smtp.gmail.com";
client.EnableSsl = true;
client.Timeout = 10000;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential("user#gmail.com","password");
MailMessage mm = new MailMessage("donotreply#domain.com", "sendtomyemail#domain.co.uk", "test", "test");
mm.BodyEncoding = UTF8Encoding.UTF8;
mm.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure;
client.Send(mm);

Send mail fail c#

I'm having problem trying to send a mail. VS give me a this error: Failure sending mail.
What i'm doing wrong!!
string from = "from#htomail.com";
string to = "to#gmail.com";
MailMessage mail = new MailMessage();
mail.To.Add(to);
mail.From = new MailAddress(from, "test", System.Text.Encoding.UTF8);
mail.Subject = "testing";
mail.SubjectEncoding = System.Text.Encoding.UTF8;
mail.Body = "Loren ipsum";
mail.BodyEncoding = System.Text.Encoding.UTF8;
mail.IsBodyHtml = true;
mail.Priority = MailPriority.High;
SmtpClient smtp = new SmtpClient();
smtp.Credentials = new System.Net.NetworkCredential(from, "password");
smtp.Port = 587;
smtp.Host = "smtp.gmail.com";
smtp.EnableSsl = true;
smtp.Send(mail);

Try doing this in your helper.cs
public static void SendEmail(string email, string subject, string message)
{
MailMessage emailMessage = new MailMessage();
emailMessage.From = new MailAddress("administrator#gmail.com", "Administrator");
emailMessage.To.Add(new MailAddress(email));
emailMessage.Subject = subject;
emailMessage.Body = message;
emailMessage.IsBodyHtml = true;
emailMessage.Priority = MailPriority.Normal;
SmtpClient MailClient = new SmtpClient("smtp.gmail.com", 587);
MailClient.EnableSsl = true;
MailClient.Credentials = new System.Net.NetworkCredential("administrator#gmail.com", "p#ssw0rd123");
MailClient.Send(emailMessage);
}
Hope it helped

send email in c#

i've tried to send email using this code..but an error occurred in smtp.Send(mail); messaging "Failure sending mail"
MailMessage mail = new MailMessage();
// set the addresses
mail.From = new MailAddress("from#gmail.com");
mail.To.Add(new MailAddress("to#yahoo.com"));
// set the content
mail.Subject = "test sample";
mail.Body = #"thank you";
SmtpClient smtp = new SmtpClient("smtp.gmail.com");
smtp.Credentials = new NetworkCredential("from#gmail.com", "password");
smtp.Send(mail);

In your code specify port number:
SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587)
Also check out this thread Sending email through Gmail SMTP server with C#

You need to set smtp.EnableSsl = true for gmail.
Take a look at this class, it should work for you:
public class Email
{
NetworkCredential credentials;
MailAddress sender;
public Email(NetworkCredential credentials, MailAddress sender)
{
this.credentials = credentials;
this.sender = sender;
}
public bool EnableSsl
{
get { return _EnableSsl; }
set { _EnableSsl = value; }
}
bool _EnableSsl = true;
public string Host
{
get { return _Host; }
set { _Host = value; }
}
string _Host = "smtp.gmail.com";
public int Port
{
get { return _Port; }
set { _Port = value; }
}
int _Port = 587;
public void Send(MailAddress recipient, string subject, string body, Action<MailMessage> action, params FileInfo[] attachments)
{
SmtpClient smtpClient = new SmtpClient();
// setup up the host, increase the timeout to 5 minutes
smtpClient.Host = Host;
smtpClient.Port = Port;
smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;
smtpClient.UseDefaultCredentials = false;
smtpClient.Credentials = credentials;
smtpClient.Timeout = (60 * 5 * 1000);
smtpClient.EnableSsl = EnableSsl;
using (var message = new MailMessage(sender, recipient)
{
Subject = subject,
Body = body
})
{
foreach (var file in attachments)
if (file.Exists)
message.Attachments.Add(new Attachment(file.FullName));
if(null != action)
action(message);
smtpClient.Send(message);
}
}
}

fill
mail.Host
and
mail.Port
Properties with proper values

You should be using the using statement when creating a new MailMessage, plus a few things you missed out like port number and enableSSL
using (MailMessage mail = new MailMessage())
{
mail.From = new MailAddress("from#gmail.com");
mail.To.Add(new MailAddress("to#yahoo.com"));
mail.Subject = "test sample";
mail.Body = #"thank you";
SmtpClient smtpServer = new SmtpClient("smtp.gmail.com");
smtpServer.Port = 587;
smtpServer.Credentials = new NetworkCredential("from#gmail.com", "password");
smtpServer.EnableSsl = true;
smtpServer.Send(mail);
}

Here's a basic GMAIL smtp email implementation I wrote a while ago:
public static bool SendGmail(string subject, string content, string[] recipients, string from)
{
bool success = recipients != null && recipients.Length > 0;
if (success)
{
SmtpClient gmailClient = new SmtpClient
{
Host = "smtp.gmail.com",
Port = 587,
EnableSsl = true,
UseDefaultCredentials = false,
Credentials = new System.Net.NetworkCredential("******", "*****") //you need to add some valid gmail account credentials to authenticate with gmails SMTP server.
};
using (MailMessage gMessage = new MailMessage(from, recipients[0], subject, content))
{
for (int i = 1; i < recipients.Length; i++)
gMessage.To.Add(recipients[i]);
try
{
gmailClient.Send(gMessage);
success = true;
}
catch (Exception) { success = false; }
}
}
return success;
}
It should work fine for you, but you'll need to add a valid gmail acocunt where I've marked in the code.

This is the function which i checked to send mail...and it's working properly.
`
private static bool testsendemail(MailMessage message)
{
try
{
MailMessage message1 = new MailMessage();
SmtpClient smtpClient = new SmtpClient();
string msg = string.Empty;
MailAddress fromAddress = new MailAddress("FromMail#Test.com");
message1.From = fromAddress;
message1.To.Add("ToMail#Test1.com");
message1.Subject = "This is Test mail";
message1.IsBodyHtml = true;
message1.Body ="You can write your body here"+message;
smtpClient.Host = "smtp.mail.yahoo.com"; // We use yahoo as our smtp client
smtpClient.Port = 587;
smtpClient.EnableSsl = false;
smtpClient.UseDefaultCredentials = true;
smtpClient.Credentials = new System.Net.NetworkCredential("SenderMail#yahoo.com", "YourPassword");
smtpClient.Send(message1);
}
catch
{
return false;
}
return true;
}`
Thank You.

Following is the C# code for Gmail Service
using System;
using System.Net;
using System.Net.Mail;
namespace EmailApp
{
internal class Program
{
public static void Main(string[] args)
{
String SendMailFrom = "Sender Email";
String SendMailTo = "Reciever Email";
String SendMailSubject = "Email Subject";
String SendMailBody = "Email Body";
try
{
SmtpClient SmtpServer = new SmtpClient("smtp.gmail.com",587);
SmtpServer.DeliveryMethod = SmtpDeliveryMethod.Network;
MailMessage email = new MailMessage();
// START
email.From = new MailAddress(SendMailFrom);
email.To.Add(SendMailTo);
email.CC.Add(SendMailFrom);
email.Subject = SendMailSubject;
email.Body = SendMailBody;
//END
SmtpServer.Timeout = 5000;
SmtpServer.EnableSsl = true;
SmtpServer.UseDefaultCredentials = false;
SmtpServer.Credentials = new NetworkCredential(SendMailFrom, "Google App Password");
SmtpServer.Send(email);
Console.WriteLine("Email Successfully Sent");
Console.ReadKey();
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
Console.ReadKey();
}
}
}
}
For reference: https://www.techaeblogs.live/2022/06/how-to-send-email-using-gmail.html

Problem in Sending Email using Gmail Settings

I can't send a email message using gmail settings. i already tried client.Host ="localhost" it's working but not in client.Host ="smtp.gmail.com".. Please help me guys.. I need use client.Host ="smtp.gmail.com".. thanks
here's my C# code:
string from = "aevalencia119#gmail.com"; //Replace this with your own correct Gmail Address
string to = "aevalencia191#gmail.com"; //Replace this with the Email Address to whom you want to send the mail
System.Net.Mail.MailMessage mail = new System.Net.Mail.MailMessage();
mail.To.Add(to); mail.From = new
MailAddress(from, "One Ghost" ,System.Text.Encoding.UTF8);
mail.Subject = "This is a test mail" ;
mail.SubjectEncoding = System.Text.Encoding.UTF8; mail.Body = "This is Email Body Text";
mail.BodyEncoding = System.Text.Encoding.UTF8;
mail.IsBodyHtml = true ; mail.Priority = MailPriority.High;
SmtpClient client = new SmtpClient(); //Add the Creddentials- use your own email id and password
client.Credentials = new System.Net.NetworkCredential(from, "iseedeadpoeple");
client.Port = 587; // Gmail works on this port client.Host ="smtp.gmail.com";
client.EnableSsl = true; //Gmail works on Server Secured Layer
try
{
client.Send(mail);
}
catch (Exception ex)
{
Exception ex2 = ex;
string errorMessage = string.Empty;
while (ex2 != null)
{
errorMessage += ex2.ToString();
ex2 = ex2.InnerException;
} HttpContext.Current.Response.Write(errorMessage
);
} // end try
here's the error:
The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required.
Much thanks guys!

You need to get and send mail to GMail by using SSL secutiry certificate
MailMessage msgMail = new MailMessage("a#gmail.com", "b#mail.me", "subject", "message body");
SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
smtp.EnableSsl = true;
smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
smtp.Credentials = new System.Net.NetworkCredential("a#gmail.com", "a");
try
{
smtp.Send(msgMail);
}
catch (Exception ex)
{
}
reference: http://social.msdn.microsoft.com/Forums/en/netfxnetcom/thread/28b5a576-0da2-42c9-8de3-f2bd1f30ded4

public static string sendMail(string to, string title, string subject, string body)
{
try
{
MailMessage mail = new MailMessage();
SmtpClient smtp = new SmtpClient();
if (to == "")
to = "aevalencia119#gmail.com";
MailAddressCollection m = new MailAddressCollection();
m.Add(to);
mail.Subject = subject;
mail.From = new MailAddress( "aevalencia119#gmail.com");
mail.Body = body;
mail.IsBodyHtml = true;
mail.ReplyTo = new MailAddress("aevalencia119#gmail.com");
mail.To.Add(m[0]);
smtp.Host = "smtp.gmail.com";
client.Port = 587;
smtp.EnableSsl = true;
smtp.Credentials = new System.Net.NetworkCredential("aevalencia119#gmail.com", "####");
ServicePointManager.ServerCertificateValidationCallback = delegate(object s, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors) { return true; };
smtp.Send(mail);
return "done";
}
catch (Exception ex)
{
return ex.Message;
}
}