We have ServerA - Exchange 2010 SP3 and ServerB - Exchange 2013 within a single domain. I have a user who uses Outlook Anywhere (2010) and is trying to open a meeting room calendar and isn't able to view it. The shared calendar adds but when you click on it all you see is "not connected" and an error about not being able to access the calendar.
Everything else with the users account seems to work. They can log in fine. The permissions are set to domain users so everyone can access the calendar. I am able to open the calendar with my account.
The Calendar is located on ServerA and the users mailbox is located on ServerB.