This is probably just a lack of fundamental understanding on my part but some communities I want to subscribe to; I'll hit the sub button, it won't change status for a while, I'll refresh and it'll say "Subscribe Pending"

A couple communities have been stuck like this for a day or so now. But other communities I'll mash the sub button a bit more then it'll switch over to "Joined"

Can communities be setup such that subscribers have to be approved by a comm mod or has my subscription request fallen into the void on the backend somewhere and I should try to subscribe again?

Thanks for any clarifications about this!