Register: ERR_TOO_MANY_REDIRECTS

I’m using UM to create a company “portal” for employees to gain access to resources that are otherwise private.
I’ve used the UM default login shortcode in the footer of the site and can login fine as admin, but if a new user hits the Register button, they get the Too Many Redirects error.
I’ve checked all UM settings but can’t get it to work.
Ideally, all new users would be defaulted to subscribers and I go in and assign higher responsibilities manually.

The page I need help with: [log in to see the link]