Issues with Exchange 2010 and Exchange 2016 coexistence
This one is primarily notes to myself... When Exchange 2016 is installed with Exchange 2010, MAPI over HTTP is enabled by default for the organization. Exchange 2010 mailboxes continue to accessed via RPC. Exchange 2016 mailboxes will use MAPI over HTTP If Exchange 2016 mailboxes have Full Access to an Exchange 2010 mailbox then Outlook Anywhere is used to connect to that secondary mailbox. If using a wildcard cert you need to set the certificate name for the EXPR outlook provider for Outlook Anywhere as msstd:*domain.com. Authentication prompts Exchange 2010 on Windows Server 2008 R2 requires a security update for Outlook Anywhere to function properly. This is a security update from 2016 (KB3140410). It "should" already be in place, but if it's not then Outlook Anywhere will cause tons of authentication popups in Outlook. https://support.microsoft.com/en-us/help/2990117/outlook-anywhere-users-prompted-for-credentials-when-they-try-to-conne I saw this manifest as Exchange