Category gallery ArcGIS Instant App template does not show organization categories if the group does not have any group categories when the app is configured.

Workaround

Alternatively, make sure the group has at least 3 group categories and then change the group in the Instant App to another random group and then change it back to the original group. Once done, notice the option to 'filter by organization categories instead of group categories' is no longer grayed out. Once flipped, the organization categories is able to be used in the Instant App.

Steps to Reproduce