Searching files only works for Admins and Editors

Everything works great with the plugin except the search box only works for users with Administrator or Editor permissions. If your permission is less it returns a 404, or searches posts rather than files. I have deactivated all other plugins with no success.

We are using the plugin as a eLearning centre for customers so the content is hidden with the plugin: Restrict Content and users must be a subscriber to view the files.

You can view the page by logging is as a subscriber
User: bob Password: bob
http://www.hirum.com.au/customer-support/elearning-centre/

https://wordpress.org/plugins/wp-filebase/