Sign Up Modal

When a user goes to sign up for a course they get the modal sign up form. I get nice little arrows showing me that the Name, Username, and Email are accepted. The Password, PW Confirmation, and Course Passcode have 'X's next to them. There is no message saying why it won't process. I've used very strong passwords and the correct course passcode, but nothing happens other than the check marks and the 'X's. How can I fix this?
Thanks!
Richard