s2member User Login Problems

Every time a user tries to log in through s2member this error message comes up on the user page in my admin:

Warning: Invalid argument supplied for foreach() in /home/content/18/5788418/html/academy/wp-content/plugins/s2member/includes/functions/users-list.inc.php on line 90

And they get taken to the welcome page, but then when they try to go to any other page it just redirects them back to the membership sign up page.

If I add the user manually through the site it seems to work fine but not when they register themselves.

I have checked that all the urls are set to http://website.com with none set to http://www.website.com as the troubleshooting guide on the s2member site suggested.

I run a few websites through wordpress but this is my only membership site and I don’t know what to do, what this means or how to fix it.

The website is: http://academy.themysticallights.com

Thanks for your help!!