AiO Event Calendar totally disappeared from front end and Admin area.

The visible parts of the Calendar are no longer there. The plugin does not show up in the control panel anywhere and the link to it just goes to the home page and the widgets are no longer displaying.
The plugin files are still on the server and the posts are still in the database.
Looks like files were updated on 3/5/16.

Site is here- https://aanassaugs-ny.org/

Can I just reinstall the plugin? I do not want to overwrite the existing events in the DB

Thanks,

G

https://www.ads-software.com/plugins/all-in-one-event-calendar/