Cannot enable Container registry feature

Hello, I need help to enable the registration of containers in my private gitlab (gitlab-ce v10.6.3), I followed the guide https://docs.gitlab.com/ee/user/project/container_registry.html, but when I try to enter the url configured page is blank . Entering as administrator of Gitlab I see that the feature is not enabled. in the logs it says nothing.

I Configure this settings:
registry_external_url ‘https://devregistry.megatrans.com.ar
registry_nginx[‘ssl_certificate’] = “/etc/gitlab/ssl/devgit.megatrans.com.ar.crt”
registry_nginx[‘ssl_certificate_key’] = “/etc/gitlab/ssl/devgit.megatrans.com.ar.key”

i already have configured gitlab-ce/mattermost and ldap authentication

thanks in advance!