Is it possible to login to the docker registry on the RedHat OpenShift Interacting Learning Portal (Playground)

I’m working on the Red Hat OpenShift Interactive Learning Portal – Playground ( and would like to push my own image to the Playground’s openshift docker internal registry.

I checked the URL of the registry using the following command.

$ oc get route -n default --as=system:admin

Then, I tried to login to the registry as follows. but I got error messages.

$ docker login -u developer -p xxxxxxx

Error message

WARNING! Using --password via the CLI is insecure. Use --password-stdin.
INFO[0000] Error logging in to v2 endpoint, trying next endpoint: Get x509: certificate is valid for *, *, *, *, *, *, *, *,,,, not 
Get x509: certificate is valid for *, *, *, *, *, *, *, *,,,, not

Does this mean the registry is not accessible from the outer world?

Source: StackOverflow