Edit: SSL part of this problem has been fixed. There is still a problem that after adding yourself to the mailing list, you are redirected to a blank screen as shown in screenshots below.
The link to the rails girls mailing list is http rather than https
I am not sure if that is intentional, but it might explain this problem I have when I try to add myself to the mailing list. (I've replicated this on mobile safari and desktop chrome browser, screenshots here are from desktop chrome browser)
here's what I see:
here's what happens if I try to submit:
