When calling free-busy, the endpoint returns an empty array or is missing busy slots.
If passing emails then the endpoint only works with
- Microsoft (primary calendar)
- Gmail (primary calendar)
Always use email addresses where possible as this will return the free-busy directly the provider. There is a limitation on how far in the future you can return free-busy within your application limit this to the shortest period which is Microsoft 62 days.
If emails does not work a backup method would be using passing calendar_id's which also works with:
- Virtual calendars
- Additional calendars
To resolve issue with emails not return free-busy please try the following:
- Have the customer run EWS test, does the (Getting user availability and confirming results against expected values) part of the test pass?
- If it is failing then please pass the following information to the mail administrator: