When a user tries to access the Calendar by using Outlook on the web, that user receives the following error message:
This calendar isn't available. Please try again later.Additionally, other users may be unable to see that user's free/busy information.
This problem can occur for one or more of the following reasons:
- Corrupted items in the user's Calendar
- Corrupted custom views
- Corrupted navigation pane settings
To resolve this problem, follow the steps outlined within Microsoft documentation.