Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact Xu If this issue just caused by outlook for Mac, we suggest you re-post this case to outlook for Mac forum by the following link: These issues usually occur when Outlook’s connection with the Exchange server is disrupted or the Outlook database is corrupted. If email could be synced using outlook for Windows, please check if the issue was caused by A/V software and Windows firewall, we suggest you disable A/V software and Windows firewall on both Exchange side and outlook for Mac side, then check if the issue could Outlook for Mac users often report issues such as Outlook for Mac Not Syncing with Exchange Server or Outlook 2016 for Mac not connecting to Exchange. And check if there are any errors in application log and post them for our troubleshooting. If the email could not be synced using outlook for Windows, we will consider this is an issue about Exchange side, please use OWA to check if email could be viewed.

For a test, we suggest you install outlook for Windows to check if emails was synced.

Outlook 2016 for mac sync errors