I am trying to create and
EventRelation over API, but I keep getting the following error even though I see
EventRelation as available sObject and "Allow Users to Relate Multiple Contacts to Tasks and Events" is enabled under Activity Settings in UI.
Object type 'EventRelation' is not supported. If you are attempting to use a custom object, be sure to append the '__c' after the entity name. Please reference your WSDL or the describe call for the appropriate names.
Is there something else I should enable or should I create these sObjects differently?