In Spring 20 release, Salesforce updated security and sharing model restricting the sharing mechanisms that you can use to grant record access to Guest Users. Guest Users can no longer be added to public groups.

For more details click here.

In order to support visibility of the calendar and data exposed by CalendarAnything, system admin need to create sharing rules for all objects that will be exposed on a force.com site.

For example, to publish a force.com site with Event Calendar, following sharing rules are required

1. Sharing rule for CA_Calendar object

2. Event/Activity sharing has to be set to Controlled by Parent and sharing rule should be added to parent object like Account

After sharing rules are in place, calendar on force.com site will display data that is visible only as defined in sharing rules.

For full check list on how to publish CalendarAnything as Force.com site click here.