Question

I have an Asp.Net site which uses google SMTP to send emails.. its working fine with normal gmail accounts using the below configuration

<smtp from="[e-mail]">
<network host="smtp.gmail.com" port="587" userName="[e-mail]" password="mypassword" enableSsl="true" /></smtp>

Now I need to use Google Apps email and smtp and I tried to change the configuration as shown below

<smtp from="[e-mail]">
    <network host="smtp.gmail.com" port="587" userName="[e-mail]" password="mypassword" enableSsl="true" /> </smtp>

But its throwing the Authentication failed error!!!
“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”

I double checked the Google EMail Settings, Username and password but still couldn’t solve it!!

Any thoughts on the issue will be a great help..

Thanks and Regards,
Anz

Answer 1

From MSDN :

Some SMTP servers require that the
client be authenticated before the
server sends e-mail on its behalf. Set
this property to true when this
SmtpClient object should authenticate
using the default credentials of the
currently logged on user. If the
UseDefaultCredentials property is set
to false, then the value set in the
Credentials property will be used for
the credentials when connecting to the
server.

---

    client.UseDefaultCredentials = false;
    smtp.EnableSsl = true;
    client.Credentials = new System.Net.NetworkCredential(username, password);
    ServicePointManager.ServerCertificateValidationCallback = delegate(object s, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors) { return true; }; 

    smtp.Send(mail);

Look to this link also.