I have found that you need to make specify where the Global Catalog Server name is (ask your admin)
Menu -> Preferences
select mail accounts, select your account name, click the 'Edit' button
in the 'Receiving Options' tab put your Global Catalog server name in (often your domain name, your OWA URL may be at example.com but your domain is corp.example.com)
Hope this helps
I have found that you need to make specify where the Global Catalog Server name is (ask your admin)
Menu -> Preferences
select mail accounts, select your account name, click the 'Edit' button
in the 'Receiving Options' tab put your Global Catalog server name in (often your domain name, your OWA URL may be at example.com but your domain is corp.example.com)
Hope this helps