I went to the community page here and searched for each one of these, trying to use the actual community name, the friendly name, and just parts of the name. Like for datahoarder I tried searches for “datahoarder”, “data”, and “hoarder” and they all came up blank. I note that your link for this one is still directly on lemmy.ml rather than through mander, and since I also have an account on lemmy.ml when I follow the direct link it shows I’m already subscribed as my lemmy user, but I can’t subscribe as my mander user. And

Also note my full link in the OP for https://mander.xyz/c/homeserver@lemmy.ml … Oddly this DOES open now, where it got the 404 error previously. Same with all the other “mander.xyz/c/???@lemmy.ml” links that you posted – I tried each one of those before I made this post and every single one of them gave a 404 error but are working now.

This all makes me wonder… is there some kind of delay between the first time someone on a server queries for a community, before that community will actually be accessible? I tried once again on the community page to search for datahoarder and https://lemmy.ml/c/datahoarder however neither one turned up that community. Another lemmy.ml community I’m looking at is “atheism”, I tried searching for it on the community page and got no results. I tried browsing to https://mander.xyz/c/ateism@lemmy.ml and got a 404 error.