It looks to me like lemmy.run is going up and down so that might be why you couldn’t access it. It timed out for me before, but I can access it now but no posts.
Edit: lemmy in general has an issue with federation, which is hopefully going to be fixed in the next update.
I see a banner, but no posts. Could it just not have any activity? Also, I’m pretty sure there’s a Linux community here, at least I think it’s this server. It’s not an admin specific one though.
The one you linked also says 0 users per month.
Lemmy.run has posts on that thread and has at least 13 users
Huh. Weird. I’d expect to not see anything if they aren’t federated with us, but I guess it’s just community activity.
Just FYI, I see no posts there when I access using the lemmy.zip web interface but I can see everything and subscribe when I access it through Liftoff on Android.