This morning, I woke to one of my multi-site installations reporting a 500 Server Error specifically citing the following:

Fatal error: Uncaught Error: Call to undefined function et_core_is_gutenberg_active() in /www/wp-content/themes/Divi/includes/builder/feature/BlockEditorIntegration.php:570

The system build spec’ is as follows:

  • Server: nginx
  • PHP: 7.1
  • WordPress: 5.0.3 (Multi-site)
  • DIVI Theme: 3.19.15

This error looks very specific and points to an issue with the DIVI theme, however, upon reporting it to Elegant Themes they pointed me to their general 500 error fix page. Since the vast majority of such issues are plugin conflicts I played along and started disabling plugins via sFTP since the wp-admin was also not available.

The first plugin I disabled (by renaming it) seemed to resolve the problem. The site came back and was working normally. Then, maybe 15 minutes later, the alarm went off( I use UptimeRobot for monitoring and alerts) indicating that the site was, once again, down. I disabled the next plugin which got it working the, some time later, down. This circle has gone on until I have almost no plugins left. It’s worth noting here that I am very selective with the plugins that I use and that I only use plugins from reputable developers with excellent development and support record.

I’m still not sure that I’ve fully resolved this issue so, expect further updates.