Troubleshooting Outlook desktop
Tip: If your Outlook desktop is not working, use Outlook for the Web to temporary look at your emails and calendars at outlook.office.com
- Ensure you have an internet connection
 - Check the connection status in the bottom right of the Outlook desktop window.
 
- Connected to: Microsoft Exchange = Healthy
 - Online = Healthy
 - Need Password = Click on Need Password and sign in using the popup dialogue box
 - Trying to Connect or Disconnected = Unhealthy
- Try restarting Outlook desktop
 - Try restarting your computer
 
 - Working Offline = In offline mode. To disable offline mode:
- Send / Receive
 - Unselect Work Offline

 
 
 
Try closing the Outlook app and re-opening- Check your sync settings.
- Select Send / Receive
 - Send/Receive Groups
 - Define Send/Receive Groups
 - Ensure Schedule an automatic send/receive every is checked with your desired minutes. 5 minutes is recommended.

 
 - Try changing the sync settings for the mailbox from Cached Exchange Mode to Online.
- Navigate to Exchange Account Settings
 - Untick Use Cached Exchange Mode...

 - Close and reopen Outlook
 - If you wish to have a cached (offline) copy of your mailbox still, navigate to Exchange Account Settings again and tick Use Cached Exchange Mode... This will refresh Outlook's sync.
 - Close and reopen Outlook