Events Calendar overwrites Events page with slug of "events"
If you have a page called "Events" and you activate the Events Calendar event to look at it, it overwrites that page so that the slug "events" is always looking for the Events Cal page. If you deactivate it and still have your original Events page under the slug "events," it will not open and just sends you back to the home page. I'll report this to Redmine. My solution on justpublics365.commons.gc.cuny.edu was to rename our Events page slug "allevents."