Member Plugin registation not working

Plugin was working great then stopped. When signing up after putting in inital info to sign up it goes to a blank screen. it was taking them to select a subscription but not anymore. i had to select allow incomplete sign ups just to make it kind of work. you can now sign up it goes to a blank screen then because i put a log in button on my menu they can click there and get to signin and select a subscribtion, buyt it is confusing for a new person.