Gitlab runner exec docker test

Hi all, when I type above command and it show message like this
Running with gitlab-runner 11.2.0 (11.2.0)
Using Docker executor with image registry.gitlab.com/xxxxxx/xxxxxx:latest
Pulling docker image gitlab-runner-helper:11.2.0 …
ERROR: Job failed: Error response from daemon: pull access denied for gitlab-runner-helper, repository does not exist or may require ‘docker login’: denied: requested access to the resource is denied (executor_docker.go:166:3s)
FATAL: Error response from daemon: pull access denied for gitlab-runner-helper, repository does not exist or may require ‘docker login’: denied: requested access to the resource is denied (executor_docker.go:166:3s)

Help me