I receive an error when trying to add an event to my Outlook.com / Office 365 email. How can I fix this?

When adding an event using the Outlook.com or Office 365 button you may receive the error

    404. The event contains errors. 

    The event you have tried to add to your calendar contains invalid event information.

    The error returned to AddEvent:

        REST API is not yet supported for this mailbox.

This is an error caused by the security settings set for your mailbox and not caused by the event from the eCQI Resource Center. If issues persist, please contact your information technology department or local administrator.

See an online article for more information.