More than 9 times out of 10 when you see this error message there is an intermittent network problem or a problem out of your control with the receiving email server. I recently ran into a problem where the connection timeouts were being caused by my smtp relays. Here is some specific information about the problem and resolution :
http://www.emailquestions.com/mail-...ail-attachments-sun-v210s-w-solaris-10-a.html
http://www.emailquestions.com/mail-...ail-attachments-sun-v210s-w-solaris-10-a.html
