F-Droid is an installable catalogue of FOSS (Free and Open Source Software) applications for the Android platform. The client makes it easy to browse, install, and keep track of updates on your device.
As with most apps in the Fediverse, the system first makes you connect to your server's web page to authenticate and authorize the app. Did you manage to get to that stage?
Same here, including when I try to search for it by name. OTOH, when I open the link in a browser instead of the f-droid app, I get a good page on f-droid.org