While sending mail from particular id I get this error, for rest of all id's its working fine,
What was the problem over here..

```
Syntax error, command unrecognized. The server response was: 
status code :0 

```

stack trace:

```
   at System.Net.Mail.SmtpConnection.ConnectAndHandshakeAsyncResult.End(IAsyncResult result)
   at System.Net.Mail.SmtpClient.ConnectCallback(IAsyncResult result)

```

---

Brief:

```
 System.Net.Mail.SmtpException: Syntax error, command unrecognized. The server response was: 
   at System.Net.Mail.SmtpConnection.ConnectAndHandshakeAsyncResult.End(IAsyncResult result)
   at System.Net.Mail.SmtpClient.ConnectCallback(IAsyncResult result)

```

---

Please help me out..