Events in Calendar Disappeared

For years, I have used the CalPress Events plugin as the calendar plugin on the website saint-albans.org. Because of problems that have developed with CalPress, I have been investigating other plugins and tried Events Calendar WD after deactivating CalPress. I didn’t particularly like Events Calendar WD, so I deactivated it and re-activated CalPress. On saint-albans.org, What’s Happening–>Calendar redirects to the following:

https://saint-albans.org/whats-happening/calendar/#action=calp_month&calp_month_offset=-1

When I go to the above URL, however, all my calendar entries are missing and, if I try to re-enter them, the website doesn’t take my entries. What do I need to do to fix this? Thanks for any help!

The page I need help with: [log in to see the link]