@julian Please find attached a summary of my nginx settings.
The back-end installation of NodeBB was done manually in a home directory, while the reverse proxy is part of on automated server solution called Webinoly. It is typically used for self-hosting WordPress, but not only. It worked pretty well before the advent of Federation capabilities, so I wasn't bothered. I just uncommented some proxy headers in /etc/nginx/apps.d/forum.n66.pl-proxy.conf and added "X-NginX-Proxy true" as per documentation. Mongodb (7.0) is provided from a deb repository as is nodejs.
I'm not sure why the web root directory as mentioned in /etc/nginx/sites-available/forum.n66.pl does not exist (root /var/www/forum.n66.pl/htdocs). I don't even have /var/www/forum.n66.pl/.
Thank you for helping me.

@julian haha now that reposting from fedi instances is possible, maybe you need to collapse the "... shared this topic N minutes ago", by default in the UI

@Jakub-Urbanowicz whatever your nginx config, if it was working before, it should not require any changes to support federation.

I would revert back to a working config if you're seeing issues with regular usage of NodeBB. Otherwise if the site is loading fine then tweaking nginx (probably) won't fix anything and the problem likely lies elsewhere.

I will look into your configs tomorrow.

@julian Updated to nodejs 22.x and nodebb 4.0.5. Still no joy with Federation. Did you manage to have a look at my Nginx settings? I have quite a few people subscribed, but not a piece of new ever showed from them. Otherwise the forum is working fine.

@julian So... I wonder if NodeBB is/can be a Fediverse instance now basically? Meaning, can registered users interact with other Fediverse instances?

I'm considering building a special interest community with NodeBB as a base. But some might want to create and/or embed media content and I'm thinking of using own PeerTube, Pixelfed instances for example for this purpose. Would a NodeBB user be able to interact with them? And can I gate areas from being public? Because of NSFW content.

@julian That's great! Any tips starting this as cheap as possible and with least amount of caring work? I've read so far you need VPS which is not only costly(?) but also backup etc would be in my hands, right? Would like to avoid that tbh.