Hi,
Thanks for using the Events Calendar.
Here on the pre-sales forum, I’m afraid we do not provide technical support. I would ask that you take any technical support questions across to our wordpress.org forum – our staff scan it periodically and other community members may also be able to help out.
The Events Calendar
Having said that you could look up the User Role Editor plugin and make sure the Contributor role does not have these capabilities checked:
read_private_tribe_events
read_private_tribe_organizers
read_private_tribe_venues
User Role Editor
Thanks again!