504 Gateway Timeout error

Error 504 happens when the web server does not get a response from a script within the allowed time. Possible causes:

• very long operations (unpacking archives, building a search index, imports);
• the script waits for external sites that do not respond or respond slowly;
• an infinite loop caused by a bug in the code or in .htaccess.

What to do

• Run long tasks with the "Scheduler" (cron) or over SSH, not in the browser.
• Check "Max execution time (s)" in "WWW" -> "PHP" -> the "php.ini" tab.
• Look for errors in "Logs".