We're using Outlook 2010 with Exchange 2010. If I create a new appointment using Outlook 2010 and add 2 users as attendees, I can see one of the user's Free/Busy schedule, but not the other user's. Instead their entire schedule is hashed out and if I place my cursor over it, I get a message that says "No Free/Busy information could be retrieved."
Now, if I sign into OWA and repeat the above process, I can see both user's Free/Busy schedule. No issues whatsoever.
Does anyone have any idea why this is happening with Outlook 2010?