sending mail error

 The message could not be sent to the SMTP server. The transport error code was 0x800ccc6f. The server response was 554 Connect to your mailbox before sending mail via this relay

please help me out i am getting the below error and i am new to .net

i am sending mail from some other domain

The message could not be sent to the SMTP server. The transport error code was 0x800ccc6f. The server response was 554 Connect to your mailbox before sending mail via this relay my

 my code is below

        string smtpServer = "relay.enago.com";
        string userName = "temp@enago.com";
        string password = "password";
        int cdoBasic = 1;
        int cdoSendUsingPort = 2;
    & ...