i can not get mail on my iMac but i can retrieve it on my phone and iPad!

what error messages do you get? Are you using Apple mail?

Very odd that junk mail arrives but other mail doesn't. Difficult to diagnose without having full access to settings but, assuming you are actually connected to the Exchange Server (you can check this by clicking Tools>Accounts and see if the indicator light is Orange in the blue box) it is possible items from your exchange account are stored in the Outlook cache - this can cause sync problems with the Exchange server. Solution is to empty the cache in Outlook so it can download all items from your Microsoft Exchange account afresh. To do this:

1. Ensure your Mac is connected to the Exchange server.
2. In the navigation pane, press Control and click the Exchange folder for which you want to empty the cache, and then click Folder Properties.
3. On the General tab, under Empty Cache, click Empty.
4. After the folder is empty, Outlook automatically downloads the items from the Exchange server.

WARNING

This procedure will delete any information that is NOT synchronized with the Exchange server, including your contacts' mail certificate.

Before emptying the cache, you should back up Outlook information that is stored locally on your computer.