When trying to subscribe to communities on other sites, I see "subscribe pending" - I found this Github issue which points to troubleshooting with CURL commands - they should return valid JSON and instead return nothing.
Posted to other communities doesn't seem to go through - I'm guessing the same problem.
After some digging, I found the nginx config in the lemmy-ansible file structure:
templates > nginx.config
However, this is highly abstracted because it's part of the Ansible install. I'm pretty sure I shouldn't edit it.
One possible clue - so far, I've been enabling federation from the UI. There's a bit in the configuration documentation that says that the lemmy.jhson needs to be updated with a federation block:
https://join-lemmy.org/docs/en/administration/configuration.html
I don't have this file in the lemmy-ansible directory.
I also tried troubleshooting the federation setup again after reinstalling the instance from scratch.
Weirdly enough, it works correctly after a reinstall. Here's what I did, if it helps anyone:
Delete the virtual server at Hetzner
Create a new virtual server
Ensure SSH still works
Run the Ansible playlist
Open the site and configure the new Lemmy instance
Do not disable federation
Create a new community and initial comment, run the curl commands noted above (I can't see this being valuable except as a confirmation that everything is working)
Block lemmygrad.ml and enable federation debugging
Search for a community on another server (I used [email protected]), open it up, then subscribe
I'm hesitant about a solution that involves reinstalling, but I'm new enough at managing virtual environments that I'm not going to look a gift horse in the mouth.