Slugs Not Working in Highend Theme

I have Events Espresso installed for some of our Workshops and Webinars. Events Espress uses a slug to show the detail page of an event. The problem is when I use the slug, the detail event does not show.

upcoming-events is the slug, but I have used events and it does not work either. I temporarily disabled Highend for the admin viewer and looked at the site with Twenty Seventeen and the content showed using the slug.

Not sure where to turn here… thoughts?

https://tbgmarketing.com/upcoming-events/wordpress-workshop/