Appointments do not synchronize to Exchange or Outlook after being created in Dynamics 365

After creating an appointment in Dynamics 365, the appointment is not synchronized to Exchange or Outlook. 

Cause 1:

Your mailbox record in Dynamics 365 is not configured to synchronize Appointments, Contacts, and Tasks. 

Cause 2:

The appointment does not meet the conditions used in your synchronization filters for the Appointment entity. 

Resolution 1: Verify the mailbox is configured to synchronize appointments, contacts, and tasks.

1. Within the Dynamics 365 web application, navigate to Settings and then click Email Configuration.
2. Click Mailboxes and then chanve the view to Active Mailboxes.
3. Open the mailbox record for the user.
4. Verify the Appointments, Contacts, and Tasks sychronization method is configured to use Server-Side Synchronization and the mailbox has been tested and enabled. The Appointments, Contacts, and Tasks Status should be Success. 
   
   If the mailbox is configured to use Microsoft Dynamics 365 for Outlook, verify the user has Dynamics 365 for Outlook installed and running on their computer. 

Resolution 2: Verify the properties of the appointment record meet the conditions in your synchronization filters.

You can view your synchronization filters in the Dynamics 365 web application by following these steps:

1. Click the gear icon and then click Options.
2. Click the Synchronization tab and then click the option to view or manage filters.
3. Locate the filter(s) for the Returned Type set to Appointment.
   
   The default filter is to only sync appointments where you are a party on the appointment but are not just the owner. This means you need to be on the Required Attendees field or the Organizer field.