The input box to enter an email on the subscription form is not appearing. The boxes for First Name and Last Name show up just fine, though. I can still enter an email and submit, but I can’t see the box:
Your theme is doing weird things: it add a new style class to the input text, ignoring the input of type email (new with HTML 5). Ask the author theme to fix it and, at least, to not hide the fields the do not address with specific styles in the theme.