Cause: No funnels are enabled, or assets are not installed.
Fix:
Go to the Funnels tab and make sure at least some funnels are enabled (toggled on).
Go to the Assets tab and confirm that funnel assets are installed. If not, download them.
Visit the Showcase page while logged out (or in an incognito window) to see how it looks to visitors.
Clear any caching plugins (WP Super Cache, W3 Total Cache, LiteSpeed Cache, etc.) and check again.