Problems with google pagespeed / nginx.

To begin: I am utterly out of my depth here, as my experience with this website has been mostly through the wordpress interface and not the back end. I took over administering this website from the developer who set it up . Please bear with me, because this is way above my pay grade ??

The site I manage, bisa-ipeg.org, has been down as a result of the google pagespeed turndown. If you go to the URL now you’ll see that error message.

I attempted to follow the basic instructions for fixing it, but the reference page (true.bisa-ipeg.org) is also reporting an error, this time for nginx (‘further configuration is required’).

I obviously can’t get into the wordpress interface, so I tried:

1. Ringing the initial developer: ‘The WordPress instance the site is on is hosted by (host) and I think you need to contact them. They may be responsble, in fact, but even if they are not they can actually do something about it. Since we can’t reach the site or the admin interface, there is very little we can do if the problem is inside WordPress.’
2. So I tried fixing the DNS with the host (there was no cname command set up previously, which was google’s suggested solution, but as the reference page is also broken I am not sure how it will help).
3. Emailed the host: ‘I don’t really know what you are trying to achieve. If you are having issues with Google Pagespeed than it’s Google you need to be talking to.’
4. Sent google an email, no response yet.
5. Tried looking myself for various files in the FTP server to see what I can find (there is no apache, no nginx, and no modpagespeed to be found in any of the folders, so I don’t actually know where this is originating).

The only way I can get to anything that reassures me that I still have a website is at the following URL: https://www.bisa-ipeg.org/?ModPagespeed=on&ModPagespeedFilters= which google tells me might be an HTML parsing problem, but I’ve no idea what to do with that information.

I think that’s everything. If you can suggest any help, I would really appreciate it. Once again, this is not my area at all, so I apologise if I haven’t conveyed the information in a correct or helpful way. I’ve no idea where this problem has come from or where to start fixing it.