Cannot select subscription type when adding new Member

Hi, i've been doing some basic setup of a WP site with the Membership plug-in. When a new user signs up, they are unable to select the subscription or continue??

This is what the text onscreen at the time, but nothing is selectable!

Members
Step 2. Select a subscription
Please select a subscription from the options below.
PurpleChips Free Access

Signup to view specialized content - no charge