From what I gathered (that is, an internet search), it's a UI-side glitch. Lemmy IS just a prototype that is being put through the meat grinder with all the Reddit refugees.
In my experience? It doesn't even make a difference. You'll see "subscribe pending" communities on your sub feed like normal.
If you unsub and resub a few times it should work anyway.
From what I gathered (that is, an internet search), it's a UI-side glitch. Lemmy IS just a prototype that is being put through the meat grinder with all the Reddit refugees.
In my experience? It doesn't even make a difference. You'll see "subscribe pending" communities on your sub feed like normal.
If you unsub and resub a few times it should work anyway.