Problem with Outlook Account Sync

[timmytwotoes]

I have the HTC Touch Pro and am having difficulty with my work email account syncing properly with the phone. When I first got the phone and setup the outlook email through exchange the emails flowed into my phone simultaneously. However a week or so ago I accidentally cleared all my data back to the phone default settings as to when I bought it. My yahoo email still shows up properly, but my outlook account only syncs when I am at work logged into our system, or when I log into the exchange network. Once I log out of the system, the incoming emails stop showing up on my phone. Can you tell me why I wouldn't be able to get my outlook email at all times of the day, even when I am not logged into the system? Really it is pointless to only have my outlook email update on my phone when I am sitting at a computer viewing. Any help or suggestions are greatly appreciated!!!