Error 504 Gateway time-out

I had to disable Clean Talk because it was causing Error 504 Gateway time-out. The website is hosted on WPEngine, and one of the techs determined that Clean Talk was sending too many requests to admin-ajax.php. Enabling “Use AJAX for JavaScript check” did not help. My last resort was to deactivate and uninstall the CleanTalk plugin. I have 20 website using CleanTalk, and unfortunately I must remove the plugin from all of my websites and seek an alternative, until you find a solution for this Error 504 Gateway time-out.

Please update me when you find a solution to the Error 504 Gateway time-out.
Thanks!

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