Unknown host exception

[Nila dhan]

Hi pals,
I am trying to send email from my application .But the exception occurs

javax.mail.SendFailedException: Sending failed;
nested exception is:
javax.mail.MessagingException: Unknown SMTP host:

What could be wrong here.Any suggestions?

BTW if i send mail from another system using the same application,it works!!!

[Ulf Dittmer]

What do you specify as the SMTP host? It looks like it is not recognized or even empty.

[Sandeep Murthy]

i) Check if you have the required jar files ( mailer.jar, activation.jar, ...) in your class path.
ii) Disable any antivirus program running while trying to send mails. The antivirus may be scanning the ports and block it.