It's not that your request is awaiting moderation, it's just a server issue. Click on it again until it says subscribe and try again. If it stays at pending, just abort and try another day.
Probably me not understanding how it works, but most lemmy.ml communities I subscribed to have this "subscribe pending" but I can still interact with them, just like you did with this thread. So I guess it's just a display issue and we are actually subscribed to those communities?