Creating a Remote Mailbox in an Exchange Hybrid Environment
- Login to the on-premises Exchange Admin Center.
- On the Recipients > Mailboxes panel, click the drop-down to add an Office 365 Mailbox.
- Fill out the webpage to create the new user object in AD and click Save. This will also create a mail-enabled user in Exchange on-prem with a remote delivery address (targetAddress) configured for the tenant address (email@example.com). This will configure the mailbox for coexistence with Office 365.
- Allow synchronization to occur between Active Directory and Azure Active Directory. By default this happens every 30 minutes by default with AAD Connect. Read http://http://www.expta.com/2016/03/how-to-schedule-and-force-sync-updates.htmlthis article to learn how to force AAD Connect to perform a manual sync.
- Sign in to the Office 365 portal and assign a license to the user for Exchange Online. At this point the mailbox is created and the user is allowed to sign in to Office 365.