Zoho Sites Member Portal Issue

Zoho Sites Member Portal Issue

I recently bought the Member Portal add on for my site and I am having an issue with users registering. I disabled public sign ups because I wanted it to be invite only. When I invite a user and they click on the link, it brings them to a page that has an email box only. When they enter their email and click the continue button, nothing happens. The only way to get the password box to show up is to reload the page. I hope you can help me in resolving this issue.

Thanks

Here is what it looks like when they first click the link: