At the time of the OP I was testing federating two nodeBB instances. ActivityPub requires HTTPS AFAIK.

I’m attempting to run a NodeBB forum. I’m only assuming that web sockets was the issue because the first search result I came up with that matched my symptoms mentioned it.

I looked up Cloudflare tunnels and tried setting one up. Some things future readers may want to know:

1. You have to set Cloudflare as your domain’s authoritative nameservers.
2. You need to set up an account (not a problem) but also have to register a payment method, even for the free tier (no me gusta).
3. Regarding NodeBB specifically, if you set up a tunnel, you can access the forum, even over HTTPS, but it fails when you try to log in. A few minutes of searching leads me to believe it has something to do with web sockets, and the solution requires you to partially expose your IP address, defeating the principle purpose for me to use cloudflare in the first place.