I'm also having the same error and I guess everyone's experiencing the error too. Maybe Admin is up to something?
The 504 means
1 the server is down or not working properly. So, it could be something to do with admins recent update?
Done. I only did the ones that look really similar to Latin characters, and it only applies to English sections. It's done at display time, so it's retroactive.
1One server did not receive a timely response from another server that it was accessing while attempting to load the web page or fill another request by the browser. This usually means that the other server is down or not working properly.
ref