Error in Documents Aprroval

Dev

hi all
while sending a Sales order document for approval i m getting an error as


"The message could not be sent to the SMTP server. The transport error code was 0x800ccc15. The server response was not available"

I have make the setup of SMTP as
My offcie smtp server name
Basic
My webmail userid
password

Is there any thing to be done or any othr suggestion to check

Regards