External user newly created can create group

Summary

I'm using the docker image gitlab-ce:10.1.0 I enabled the 'New users set to external' in the setting, but new register user can still create group and project

Steps to reproduce

1. Enable 'New users set to external' && 'Sign-up enabled' in setting by root
2. Regist a new user

What is the current bug behavior?

The new user has the rights to create group and project

What is the expected correct behavior?

The new user won't be able to create group or project

Relevant logs and/or screenshots