That fixed it, thanks so much!
I don’t have any other caching plugins, but my website can still be accessed from several devices on which I’m not signed in. The only plugins currently activated on my site are: Google Analytics Dashboard for WP, HostGator WalkMe Plugin, Jetpack by WordPress.com, Under Construction, Varnish HTTP Purge, and WordPress Importer. I did update to the latest version of Under Construction this morning but am still experiencing the same issue of not seeing the Under Construction page.
Thank you for your response. I deactivated WP Super Cache and the fatal error has stopped. However, my dashboard now says that Under Construction mode is currently enabled, but I have tried from several other devices and am still able to view my site (no Under Construction landing page). Does Under Construction take some time to activate? Please advise.
