Consider the following scenario:
- You're working in an Office 365 hybrid environment.
- You have a mailbox that is hosted on an on-premises server that is running Microsoft Exchange Server 2010.
- An Exchange Online user adds the mailbox to an Outlook profile as an additional mailbox.
- The Outlook Anywhere (RPC/HTTP) connection of the on-premises mailbox to the Outlook client is disabled.
In this scenario, some users cannot expand the folders of the on-premises mailbox, and they can see only free/busy data in the Outlook calendar even though they have Full Access or Editor/Reviewer permissions to this mailbox.
To fix this issue, add the on-premises mailbox as an additional account in the Outlook client. To do this, follow these steps:
- Select File > Info > Account Settings.
- On the E-mail tab, select New.
- On the Auto Account Setup page, enter the mailbox name, the email address, and your account password.
- Select Next.
Note Make sure that you have Full Access permission to this mailbox.