504/502 errors plauging our site

If you think a plugin is causing the problem, disable all plugins by renaming the wp-content/plugins folder. Then put the plugins (in the subfolders of wp-content/plugins) back into a new wp-content/plugins folder.

Do a couple/three at a time to see if you can find a bad plugin.

You might also reload WP 4.7.2 via the sites Updates page (even if you are already at 4.7.2). If you were not at 4.7.2 (insert standard ‘do your updates!’ advice here), then you have some additional work….get up to 4.7.2 first, then ensure all plugins are current.

5xx errors are often server-based, not WP-based (although could be SQL problems), so talk to your host and ask if they are noticing SQL problems on your (possible shared) server.

Updates are important….there are tons of WP sites that are getting hacked via the RESTFUL problem fixed by 4.7.2.