Facebook SDK FB.GetLoginStatus Load denied by X-Frame-Options (Firefox Only)

Question

I have this web application login page that calls FB.GetLoginStatus() from the Facebook JavaScript SDK after the document is done loading. This worked perfectly fine on all

Answer 1

OK, after fighting this for a few hours I finally found out what was bothering Firefox: the website site URL field in the app's Facebook Dashboard settings.

The issue wasn't even with ngrok or a missing signed certificate, it was the fact that the website in the settings had the production domain (.app) instead of the ngrok one I'm currently using for development (eu.ngrok.io).

The only reason I managed to pinpoint this back to the dashboard settings is because I have 2 Facebook apps, and the other one was working fine, so I imagined it might be a misconfiguration in the settings that was causing the issue (Facebook has a shitty standard in place for explaining/handling errors — it's like shooting in the dark until you hit something when using their SDK's).

What I don't understand here is why the heck only Firefox seems to have a problem with this setting being misconfigured or why the issue disappeared out of nowhere from one day to the next for Chrome. Anyways, if I managed to help anyone else fix anything similar with this thread than this headache has been worthwhile.

Peace out ✌