Users/members cannot log in to website

Hello,

I have installed the Membership plugin on a client's site. http://grentone.com/

Everything was working fine and now the client states that users cannot log in. When I went to try to access the site via http://grentone.com/wp-admin/ or http://grentone.com/log-in/ I get redirected to the http://grentone.com/register/ page.

I was finally able to access the admin log in page via a url that was saved in my browser http://grentone.com/wp-login.php?redirect_to=http%3A%2F%2Fgrentone.com%2Fwp-admin%2F&reauth=1

I need help getting the log in working for both authors/owners of the site and also members as well. Thank you.

Steve