i'm not even sure if this a Subscribe2 issue, but my client's subscribe form was working fine up until recently. she just noticed yesterday it wasn't working. when you enter your email and click the 'subscribe' or 'unsubscribe' button, you get a 501 error...
501 Not Implemented
We are sorry to be unable to perform the method POST at this time or to this document.
neither of us has touched the wordpress admin in weeks. today i updated the plugin thinking it might help but no luck.
i'm not an expert developer so if you could provide any feedback/help using dumbed-down vocabulary, i'd appreciate it! =o)