oc login -u system:admin
Server [https://localhost:8443]:
The server is using a certificate that does not match its hostname: x509: certificate is valid for ec2-52-90-239-116.compute-1.amazonaws.com, ip-172-18-3-207.ec2.internal, kubernetes, kubernetes.default, kubernetes.default.svc, kubernetes.default.svc.cluster.local, openshift, openshift.default, openshift.default.svc, openshift.default.svc.cluster.local, 172.18.3.207, 172.30.0.1, 52.90.239.116, not localhost
You can bypass the certificate check, but any data you send to the server could be intercepted by others.
Use insecure connections? (y/n): y

Authentication required for https://localhost:8443 (openshift)
Username: system:admin
Password:
error: username system:admin is invalid for basic auth