I've been fighting with this plugin for several days, and only got it to work to the point that it is right now by uninstalling, deleting all the files, and dropping the related database tables. Twice.
Currently, it is generally working, with two important exceptions, the first being more important than the second.
First of all, I note that none of the short codes are working- including [subscriptionform]. I have tried inserting it on several pages because it won't show up where it belongs, on the subscribe page. This had been one of the things that had worked before I did all of the reinstalling of the plugin, but does not work any longer.
Interestingly, the custom short code that I made does display content... although, ironically, the access level is supposed to hide it. But there is one short code that is working. Sort of.
Yes, I have the short code visibility defaulted as visible and all the access levels have been set to display short codes.
The second thing is that when I set the Protected content page, when I test the different access levels by assigning the 'stranger' to each one in turn, I find that some of them redirect to the protected content page, even when they have access to the page according to the settings. This should not happen, since the pages in question are viewable at least in some measure by all of the access levels. If I set the protected content page to nothing (select a page) then everything works as it should. Since I do have some pages that I want to be completely hidden to some users eventually, it is important that I get this to work.
I have the latest versions of both membership and wordpress installed.