I am able to ping smtp.mail.yahoo.com from my system but when i send email from following code using yahoo address it gives error transport failed to connect to server.
The same code successfully sends the email from gmail account.
I am using port 465 for yahoo.
MailMessage oMsg = new MailMessage();
oMsg.From = from.Text;
oMsg.To = to.Text;
oMsg.Subject = "Hi";
oMsg.BodyFormat = MailFormat.Html;
oMsg.Body = msg.Text;
oMsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpserverport", port);
oMsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpserver", host);
oMsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusing", 2);
WebProxy proxy = WebProxy.GetDefaultProxy();
if (proxy.Address != null)
{
oMsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/urlproxyserver", proxy.Address.Host);
oMsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/proxyserverport", proxy.Address.Port);
}
oMsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpusessl", true);
oMsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", "1");
oMsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusername",from.Text);
oMsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword", pass.Text);
// ADD AN ATTACHMENT.
/* MailAttachment oAttch = new MailAttachment(path+ "\\Image.bmp", MailEncoding.Base64);
oMsg.Attachments.Add(oAttch);*/
SmtpMail.SmtpServer.Insert(0,host);
if (proxy.Address != null)
MessageBox.Show("Sending via proxy settings: " + proxy.Address.ToString());
try
{
SmtpMail.Send(oMsg);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
oMsg = null;
Any ideas why this error occurs?
Being able (or not) to ping a host does not say anything about whether you will be able to connect to a particular service on it. For that, you need to try to actually establish a connection. (And of course, the fact that you can establish a connection does not necessarily imply that the service in question is working properly.)
Usually, it's a good idea to use telnet to try connecting to the remote host on the port in question. The syntax on the command line is simply telnet host.fqdn.example.com portnumber. This will tell you if there is anything at all at the other end of the pipe responding to connection attempts, which is a first step in determining where the problem is.
Second, it's usually a good idea to trim the code to the minimal version that exhibits the problematic behavior, and include the full code to show the problematic behavior. You are using a number of variables in your code which we really know nothing about.
Some ISPs block outgoing connections to the SMTP ports on hosts other than their own mail servers, to reduce the amount of outgoing spam. Maybe there is a typo in the value in host? Maybe you are inadvertantly using some unexpected MailMessage implementation? And so on.
That said, I would definitely first try to connect to the mail server in question manually, through a proxy if you are using one to connect using that code. If that doesn't work either, then your problem at least has nothing to do with the code in the question, and you can look elsewhere (in which case one possible candidate would be ISP filters; maybe they have a list of allowed external SMTP hosts and Yahoo's isn't on it?).
Related
I have an service that needs to send out automated emails on failures. I feel like i have it set up but i keep on receiving the following error:
Service not available, closing transmission channel. The server response
was: 4.3.2 Service not available
I cant quite figure out where i went wrong, but here is my code:
public static void AutoEmail()
{
try
{
SmtpClient newClient = new SmtpClient();
newClient.Host = "host name";
newClient.Port = Port number;
newClient.Credentials = new System.Net.NetworkCredential(
"username", "password");
MailMessage mail = new MailMessage();
mail.To.Add(new MailAddress("something#email.com"));
mail.Body = "This is a test message.";
mail.Subject = "Test - " + DateTime.Now;
mail.From = new MailAddress("something2#email.com");
newClient.Send(mail);
}
catch (Exception ex)
{
Log.WriteException("Error in Email", ex);
}
}
Any help would be much appreciated. Thanks!
Are you sure SMTP server you are using permits applications to send emails? I had met with similar issue and root cause was Exchange server was rejecting the send request due to insufficient permissions. And I have the same steps in my code as in yours. Check for permissions.
Have you tried
newClient .UseDefaultCredentials = true;
Does it help ?
The SMTP server name only works on a computer within the network that contains that SMTP server.
You need to make sure SMTP server's host name and port number in your program is correct. All the other code in your program seem fine.
I experienced the same error before. At the end, I changed to the correct host name and port number and everything works.
For example, Outlook.com Or Hotmail email accounts
host="smtp-mail.outlook.com" port="25" enableSsl="true"
https://www.outlook-apps.com/outlook-com-pop-settings/
I know there are various thread out there related to this problem but i was unable to take any of the responses on those thread and make it work on my server.
So let try to see if someone can help me out here.
99% of the emails go out properly and few actually return with that error.
My code looks like this
MailMessage mm = new MailMessage(Settings.EmailCustomerService, to, subject, body);
mm.SubjectEncoding = Encoding.UTF8;
mm.BodyEncoding = Encoding.UTF8;
mm.IsBodyHtml = true;
MailAddress add = new MailAddress(Settings.EmailCustomerService, "Customer Service");
mm.From = add;
try
{
SmtpClient client = new SmtpClient(Settings.EmailSMTP);
client.UseDefaultCredentials = false;
client.Credentials = new NetworkCredential(Settings.EmailUser, Settings.EmailPwd);
System.Threading.ParameterizedThreadStart threadStart = new System.Threading.ParameterizedThreadStart(SendInThread);
threadStart.Invoke(new SendInThreadParams
{
client = client,
Message = mm
});
}
finally
{
mm = null;
}
Actually the Credentials code was added later but my code was run OK even without it. It just happen that 1% of the email never make it to the recipients and adding those 2 lines for Credentials did not make a difference.
The Settings.EmailUser is just a user on the server where the SMTP runs, but i have NOT attach it to nowhere.
I bet that's the problem.
The SMTP Server Relay is set to use 127.0.0.1 and the FQDN is just the name of the machine (something like "Machine1" ...nothing with a domain.com name)
The error I'm getting is this
Reporting-MTA: dns;Machine1
Received-From-MTA: dns;Machine1
Arrival-Date: Wed, 30 May 2012 23:08:36 -0700
Final-Recipient: rfc822;test#email.net
Action: failed
Status: 5.5.0
Diagnostic-Code: smtp;550 Access denied - Invalid HELO name (See RFC2821 4.1.1.1)
Return message emailed back was:
> This is an automatically generated Delivery Status Notification.
Delivery to the following recipients failed.
test#email.com
Thanks in advanced...
In addition to the message/delivery-status attachment, the DSN will usually have the returned message. For this sort of issue you should post the headers of the returned message and the DSN as well.
It looks to me like your server has accepted the message, but has an error transmitting it onwards. If your server had rejected it, your code would have thrown an exception. So your server Machine1 accepted it, attempted to transmit it to email.net, but email.net rejected it. Machine1 then generated a DSN (delivery status notification, in your case an NDR = Non-Delivery Report).
In other words it is a configuration error with the email server not a code problem. Almost certainly the issue is that the email server is not set up with an FQDN as you stated.
As a configuration problem, it belongs on ServerFault.
Based on BEN answer I realized that I was missing the PRIMARY DND SUFFIX.
Mainly in order to find out your FQDN, you need to simply:
1) Open a Command Prompt
2) Type "ipconfig /all"
Read your HOST NAME + PRIMARY DNS SUFFIX.
My DNS SUFFIX was emtpy so i went and added using this link
http://www.simpledns.com/kb.aspx?kbid=1227
And then rebooted the machine.
Now the code works like a charm.
Thanks BEN !!!
I know there's a lot of example on how to send an email using C# but I am really running into some issues and I can't make it to work.
I always get "Failure sending mail" error, Unable to connect to the remote server - No connection could be made because the active machine actively refused it (IP address here).
What does this error mean? And how do I fix this?
Any help will be much appreciated
Here's the code that I've been using: (although I already did try a lot of things)
string SendersAddress = "test#gmail.com";
string ReceiversAddress = "test1#gmail.com";
const string SendersPassword = "test-pass-here";
const string subject = "Testing";
const string body = "Hi This Is my Mail From Gmail";
try
{
SmtpClient smtp = new SmtpClient
{
Host = "smtp.gmail.com",
Port = 587,
EnableSsl = true,
DeliveryMethod = SmtpDeliveryMethod.Network,
Credentials = new NetworkCredential(SendersAddress, SendersPassword),
Timeout = 3000
};
MailMessage message = new MailMessage(SendersAddress, ReceiversAddress, subject, body);
smtp.Send(message);
}
catch (Exception ex)
{
}
Thanks!
It sounds like you're running into issues connecting to the SMTP server.
Make sure the firewall is open on port 25, and that you actually have an SMTP server running wherever you're trying to establish your connection.
You're trying to establish an SSL connection to gmail on port 587. That port must be used with TLS, not SSL.
Use port 465 instead.
Also note that the Timeout property is expressed in milliseconds, so 3000 can be a little short, depending on your network. Try using a more permissive value, like 30000.
Also worth checking that your anti-virus is not blocking port 25, I have been caught by that before!
Same for me in past few days,
Easy solution:
First check if everything is OK with Telnet, then try to do the same in C#.
Here is a good intro : http://www.wikihow.com/Send-Email-Using-Telnet.
Just beware that some servers use the EHLO command instead of HELO
EDIT:
take a look at the way that you can connect to SMTP server of Google here
I want to test connection is established without sending mail.My code is below.I have put wrong email and password but i m not getting any exception.I don't want to test with email send.
try {
SmtpClient smtpClient = new SmtpClient("smtp.gmail.com", 587);
NetworkCredential credentials = new NetworkCredential(textboxprimarymail.Text, textBoxpassprimary.Text);
smtpClient.Credentials = credentials;
connectionestablish.Text = "Connetion Established";
connectionestablish.ForeColor = System.Drawing.Color.ForestGreen;
}
catch {
connectionestablish.Text = "Connetion Error";
connectionestablish.ForeColor = System.Drawing.Color.Red;
}
This question is a duplicate. Basically, there is no way. As stated in another answer here:
There is no way.
SmtpClient can not validate
the usernamepassword without
contacting the serve it connects to.
What you could do is do it outside
SmtpClient, by opening a TCP
connection to the server... but
authentication CAN be complicated
depending how the server is
configured.
May I ask WHY you need to know that
before sending? normal behavior IMHO
would be to wrap sending in
appropriate error handling to catch
exceptions here.
How to validate smtp credentials before sending mail?
I'm using the following code which appears to work perfectly every time on Vista/Win7.
private void SendEmail(string subject, string body, string attach)
{
using (MailMessage message = new MailMessage("username#gmail.com", "username#gmail.com", subject, body))
{
message.IsBodyHtml = true;
if (!string.IsNullOrEmpty(attach))
{
Attachment attached = new Attachment(attach);
message.Attachments.Add(attached);
}
SmtpClient client = new SmtpClient("smtp.gmail.com", 587)
{
Credentials = new NetworkCredential("username#gmail.com", "password"),
EnableSsl = true,
DeliveryMethod = SmtpDeliveryMethod.Network
};
client.Send(message);
}
}
However on Windows XP I'm getting:
No connection could be made because the target machine actively refuses it
I've checked and Windows firewall is completely disabled...
Try from the Windows machine the following:
windows key + r
Type cmd
Type telnet smtp.gmail.com 587
If it says connection refused or similar then it's a firewall or network problem, unrelated with the code.
Hard to say if this is it, but we had that problem at one point, and it was an antivirus utility that was the culprit.
Are you using the same version of System.Net.Mail on all three systems ?
Also, could be related to the Windows Firewall blocking connections (or some other firewall).
I doubt this has anything to do with the OS, that type of exception is usually bubbled up from inner ones. Trap the exception and have a look into the inner exceptions and see what the real problem is.
However, this sort of problem is usually a firewall blockage, the remote smtp server is blocking incoming requests or your machine is blocking outgoing requests on port 25.