"Sign Up Box" not working - Studio theme

Hello,

On "Branding Settings" I have the "Sign up box" set to show ("yes"). It is showing up, but the button that it generates links to an URL that apparently doesn't exist. It links to http://www.golfdu9.com/register/ which just redirects back to the home page. I would be happy to input a "Sign up custom link' but I don't know what that might be. http://www.golfdu9.com/wp-login.php?action=register also redirects to the home page. I am completely stumped here. As of right now I have NO way for anyone to register and I can't even find a working registration form. Some help would be very much appreciated!

Thanks,
Mimi