Has anyone gotten single sign on using simplesamlphp to work with Acquia's platform? I kept getting the error "This site can’t be reached dev.example.com unexpectedly closed the connection." when tried to login with the local drupal admin account. With any other domain user, simplesamlphp_auth would failed to authenticate with "Unrecognized username or password." It seemed that login to /saml_login/ should redirect to our IdP shibboleth authentication but it's not. Instead it redirects to /user/login/ for login.
I've created the issue in Drupal module simplesamlphp_auth.