Calendar Stuck on Loading

The WP Full Calendar is always stuck on loading in all browsers (Chrome, IE, Mozilla) on the following sites:

https://ihtinstitute.com/hospitality-training-events/
https://sbhbusiness.com/st-barth-events/
https://sci1st.com/business-training-events/

I have already disabled all plugins and no change. I have tried changing themes and no change.

The calendar is connected to https://www.wp-events-plugin.com.

Does anyone have any suggestions or fixes?

Thanks

https://www.ads-software.com/plugins/wp-fullcalendar/