Error while sending an email form my website with SmtpClient.

Posted on 2009-05-14
Last Modified: 2013-12-17
I'm developing a website with ASP.NET 2005 and C#. I tried to send emails from my website
using the code I put in code section.
it gives me the follwing error:
"Bad sequence of commands. The server response was: This mail server requires authentication when attempting to send to a non-local e-mail address. Please check your mail client settings or contact your administrator to verify that the domain or address is defined for this server"
If I change the mairTo to ""  which is my website, it'll work fine. But this way I can only send emails to my own website.!
Please help me how to solve my problem.
string mailFrom =  "";
 string mailTo =      "";;
        System.Net.Mail.MailMessage email = new System.Net.Mail.MailMessage("", mailTo);
        email.Subject = "subject";
        email.IsBodyHtml = true;
        email.Body = " body of the email";
        System.Net.Mail.SmtpClient mailClient = new System.Net.Mail.SmtpClient();
        System.Net.NetworkCredential basicAuthenticationInfo = new System.Net.NetworkCredential("", "my_password", "");
        //mailClient.Host = "";
        mailClient.Port = 25;
        mailClient.UseDefaultCredentials = false;
        mailClient.Credentials = basicAuthenticationInfo;
        catch (Exception ex)
           return ex.string();

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Question by:Elham_Seif
LVL 70

Assisted Solution

by:Éric Moreau
Éric Moreau earned 100 total points
ID: 24384174
you will surely find your solution from

Assisted Solution

by:Faheem Shaikh
Faheem Shaikh earned 100 total points
ID: 24384430
Have a look here for some causes and resolutions of this:

Accepted Solution

Ramone_Hamilton earned 300 total points
ID: 24384612
Are you using your own smtp server?  If so check to make sure that it is capable of sending e-mails outside of your domain.  I believe that most webmails such as hotmail, yahoo or gmail won't accept your e-mails unless they are coming from a legit exchange or smtp server connected to a static ip address.
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Author Comment

ID: 24385627
I got confused reading those long sites about emails.
Would you please read my code and tell me what's wrong with the code?
What can I use instead, to make it run correctly.
The one that can correct my code will get the points.
Thanks in advance.

Expert Comment

ID: 24385753
You haven't set the address of the smtpclient you are sending from.  Try this:

System.Net.Mail.SmtpClient mailClient = new System.Net.Mail.SmtpClient("");

Author Comment

ID: 24386458
Hi Ramone_Hamilton
my host is
what should I write instead of "" in the code you said?

Expert Comment

ID: 24386804
Are you running your own smtp service or is your web page being hosted by another company?

Author Comment

ID: 24401179
Hi Ramone_Hamilton
My website is hosted by another company.
How can I run my won smtp service? And what's the diffrence?

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