Develop Reference

Can't send mail to other mail-domain (only within same)

I can only send mail within same mail-domain, but not outside it. Am I missing something?
try {
MailMessage mail = new MailMessage("noreply#company.com", "user#mail.com");
SmtpClient client = new SmtpClient();
client.Port = 25;
client.EnableSsl = true;
client.Timeout = 10000;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Host = "smtp.company.com";
mail.Subject = "Thanks...";
mail.Body = "text...";
client.Send(mail);
} catch (Exception ex) {
Response.Write(ex.ToString());
}
Error message when sending to other mail-domain:
System.Net.Mail.SmtpFailedRecipientException: Mailbox unavailable. The
server response was: 5.7.1 Unable to relay at
System.Net.Mail.SmtpTransport.SendMail(MailAddress sender,
MailAddressCollection recipients, String deliveryNotify, Boolean
allowUnicode, SmtpFailedRecipientException& exception) at
System.Net.Mail.SmtpClient.Send(MailMessage message)
I've no control over the smtp host, but I should be able to send to other mail-domain.

Mail sending Error c# [duplicate]

This question already has answers here:
Gmail Error :The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required
(21 answers)
Closed 8 years ago.
How to solve this SMTP Error problem? When I'm sending mail I'm facing this error message. Sending mail using local system is not a problem. Does anyone know the solution to this problem?
System.Net.Mail.SmtpException: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required.
at System.Net.Mail.MailCommand.CheckResponse(SmtpStatusCode statusCode, String response)
at System.Net.Mail.MailCommand.Send(SmtpConnection conn, Byte[] command, MailAddress from, Boolean allowUnicode)
at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, Boolean allowUnicode, SmtpFailedRecipientException& exception)
at System.Net.Mail.SmtpClient.Send(MailMessage message)
at admin_booking.btninvoicemail_Click(Object sender, EventArgs e) in c:\inetpub\vhosts\starlineroadways.com\httpdocs\admin_booking.aspx.cs:line 596
code:
System.Net.Mail.SmtpClient smtp = new System.Net.Mail.SmtpClient();
smtp.Host = "smtp.gmail.com";
smtp.EnableSsl = true;
smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
smtp.Credentials = new System.Net.NetworkCredential("xx#gmail.com", "xx");
System.Net.Mail.MailMessage oMsg = new System.Net.Mail.MailMessage();
MailAddress #add = new MailAddress(txtsendemail.Text);
oMsg.From = new MailAddress("xx");
oMsg.To.Add(#add);
oMsg.Subject = "xxx";
oMsg.Body = msgbody2;
oMsg.IsBodyHtml = true;
smtp.Send(oMsg);

You can try this.
MailMessage Mail = new MailMessage();
Mail.From = new MailAddress("xx#gmail.com");
Mail.To.Add(txtsendemail.Text);
Mail.Subject = "xxx";
Mail.Body = msgbody2;
SmtpClient smpt = new SmtpClient();
smpt.Credentials = new NetworkCredential("xx#gmail.com", "xx");
smpt.Port = 587;
smpt.Host = "smtp.gmail.com";
smpt.EnableSsl = true;
smpt.Send(Mail);

Sending an email using c#

I'm trying to figure out how to create a simple contact page in order to send an email. Right now I'm just testing but i'm not getting any error message.
Here is my code:
protected void btnSend_Click(object sender, EventArgs e)
{
MailMessage msg = new MailMessage();
msg.To.Add(txtFrom.Text);
msg.Subject = txtSubject.Text;
msg.Body = txtMessage.Text;
SmtpClient smtp = new SmtpClient("localhost");
smtp.Send(msg);
Response.Write("Your email was sent");
}

Do you have an Smtp service running on your localhost? If not you can use Gmail's smtp service for testing.
SmtpClient client = new SmtpClient("smtp.gmail.com", 587);
client.Credentials = new NetworkCredential("<your gmail login>", "<your gmail password>");
client.EnableSsl = true;

As others have pointed out, you probably don't have the localhost as a real mail server. To get a better idea, turn Tracing on and change your code to something more like this:
protected void btnSend_Click(object sender, EventArgs e) {
Trace.Write("btnSend_Click initialized");
string resp = "An unknown error occured.";
using (MailMessage msg = new MailMessage()) {
try {
msg.To.Add(txtFrom.Text);
msg.Subject = txtSubject.Text;
msg.Body = txtMessage.Text;
SmtpClient smtp = new SmtpClient("localhost");
Trace.Write("smtp client created.");
smtp.Send(msg);
Trace.Write("smtp message sent.");
resp = "Your message was sent.";
} catch (Exception ex) {
Trace.Warn("Smtp Error", ex.Message);
resp = "There was an error sending your message.";
}
}
Response.Write(resp);
Trace.Write("btnSend_Click completed");
}

You must specify a From address like this:
msg.From = new MailAddress("noreply#noreply"); // Use a real address, of course
Because you are not getting an exception, I wonder if btnSend_Click is getting hit at all...
Other things to look at:
Is your txtFrom.Text being overwritten on postback? You might hardcode your email address during debugging.
Try 127.0.0.1 instead of localhost.

SmtpException While sending mails in a bulk of 3 or more

I am using SmtpClient to send emails.I am using the same code for last 2years,but from last day when i send 3 or more emails together one of them will fail.When i sent the failed one again it will sent out.Please help me i am using aibn.com mail server.
public bool SendMail(string p_strFrom, string p_strDisplayName, string p_strTo, string p_strSubject, string p_strMessage , string strFileName)
{
try
{
p_strDisplayName = _DisplayName;
string smtpserver = _SmtpServer;
SmtpClient smtpClient = new SmtpClient();
MailMessage message = new MailMessage();
MailAddress fromAddress = new MailAddress(_From,_DisplayName);
smtpClient.Host = _SmtpServer;
smtpClient.Port = Convert.ToInt32(_Port);
string strAuth_UserName = _UserName;
string strAuth_Password = _Password;
if (strAuth_UserName != null)
{
System.Net.NetworkCredential SMTPUserInfo = new System.Net.NetworkCredential(strAuth_UserName, strAuth_Password);
smtpClient.UseDefaultCredentials = false;
if (_SSL)
{
smtpClient.EnableSsl = true;
}
smtpClient.Credentials = SMTPUserInfo;
}
message.From = fromAddress;
message.Subject = p_strSubject;
message.IsBodyHtml = true;
message.Body = p_strMessage;
message.To.Add(p_strTo);
try
{
smtpClient.Send(message);
Log.WriteSpecialLog("smtpClient mail sending first try success", "");
}
catch (Exception ee)
{
Log.WriteSpecialLog("smtpClient mail sending first try Failed : " + ee.ToString(), "");
return false;
}
return true;
}
catch (Exception ex)
{
Log.WriteLog("smtpClient mail sending overall failed : " + ex.ToString());
return false;
}
}
Got the following error message
smtpClient mail sending Failed :
System.Net.Mail.SmtpException:
Failure sending mail.
System.NullReferenceException:
Object reference not set to an instance of an object.
at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port)
at System.Net.Mail.SmtpClient.Send(MailMessage message)
--- End of Inner Exception Stack Trace ---
at System.Net.Mail.SmtpClient.Send(MailMessage message)

I have changed my mail server and now it is working fine.May be it depends by some mail service restriction to prevent flooding and/or spam.

Issue sending email using Gmails SMTP server

Ive written an application which sends notifications to people via email. For testing purposes im using Gmails SMTP server. Using the below code im testing but im randomly getting the below error.
I'm using smtp.gmail.com on port 587
System.Net.Mail.SmtpException: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at
at System.Net.Mail.MailCommand.CheckResponse(SmtpStatusCode statusCode, String response)
at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, SmtpFailedRecipientException& exception)
at System.Net.Mail.SmtpClient.Send(MailMessage message)
at EmailAlertService.Email.sendMail(String subject, String body, String[] recipients, String from, String& error)
About 1 out of 5 emails generates this exception.
I'm using the same credentials and to/from address combo for every test.
Any idea if its something im doing or is it Gmails servers throwing a fit!
public bool sendMail(string subject, string body, string[] recipients, string from, ref string error)
{
bool success = recipients != null && recipients.Length > 0;
if (success)
{
SmtpClient smtpClient = new SmtpClient
{
Host = hostName,
Port = port,
EnableSsl = true,
UseDefaultCredentials = false,
Credentials = new System.Net.NetworkCredential(username, password)
};
using (MailMessage gMessage = new MailMessage(from, recipients[0], subject, body))
{
Console.WriteLine(recipients[0]);
for (int i = 1; i < recipients.Length; i++)
{
Console.WriteLine(recipients[i]);
gMessage.To.Add(recipients[i]);
}
try
{
smtpClient.Send(gMessage);
success = true;
error = string.Empty;
}
catch (Exception ex)
{
success = false;
error = ex.ToString();
}
}
}
else
error = "No destination email addresses supplied";
return success;
}