Instance admin questions

Hello, I recently spun up a Lemmy instance. It kind of works but I observe some weird behaviour. For example, searching communities works very randomly, some I found some I don't and I don't see any pattern. Sometimes I hit "search" and get 0 results but then I reload the page a results appear? Some other very popular communities in very popular servers I don't find at all (even if those servers are in my "federate" list. What am I missing?