your i.t. guy wants you to know...if an email is returned as undeliverable, it likely won't go through the 2nd, 3rd, or even 10th time you try to REsend it.
The only end result of trying to send an email that many times is frustration. Check for the underlying issue first (is your computer connected to the network?) before trying to send it over, and over, and over again. If you cannot decipher the message error, forward it over to I.T. and they will be able to tell you exactly what is causing the failure and how it can be remedied.