Cannot receive or send emails

Hi,

I have a problem to send and receive emails with my emails accounts. Most of the time, it cannot send or receive emails. I have checked the delivery report, and it said:

Pending
4/30/2013 1:30 PM
The message was submitted to remote site.

4/30/2013 2:07 PM
Message delivery is taking longer than expected. There may be system delays. For more information, contact your helpdesk.

Hence, I wonder how to solve this problem?
Thanks!

Ivan