WordPress Speed Up Service | WordPress Website Maintenance Packages Reply To: Getting a warning regarding error., by Soumanta Bhowmick You must, 1. Deactivate all plugins and re-activate them one by one to see which plugin causes this. 2. Switch to wordpress default theme ( twentyfourteen, twentyfifteen etc ) to see if your current theme is causing this. 3. Take a backup of entire website & Update WordPress to its latest version. Reply To: Getting a warning regarding error.