Hello, it may be the fetching problem as you need to search for it first before the community fetches it. Other than that, there seemed to be a problem searching for them with the exclamation mark and when not using the exclamation mark the community does show up but no join ability, but that problem seems to be gone on Lemmy.world after they updated.

Since you are on Lemmy.zip, I don’t know if it’s a similar problem, or something else though, so sorry if this isn’t helpful for your case, just trying to tell you what I know, hopefully this gets fixed soon!