Interesting. You can also try https://poptalk.scrubbles.tech/c/popheads. On the website I know there's a bug where it doesn't show a loading spinner either, so it may take a few seconds after clicking search for it to show up even though it looks like it's not doing anything.
Lemmy.ml is also inundated with new members right now, they're actually 404ing for me right now, so they may be having issues connecting.