Before using the podman login command to sign into registry.redhat.io, the following curl command can be used to determine if your username and password for registry.redhat.io are valid.

curl --location --user <username>:<password> "https://sso.redhat.com/auth/realms/rhcc/protocol/redhat-docker-v2/auth?service=docker-registry&client_id=curl&scope=repository:rhel:pull" -v

If you are using a proxy server, the --proxy and --proxy-user options can be included.

curl
--location
--proxy <hostname or ip address of your proxy server>:<port>
--proxy-user <proxy server username>:<proxy server password>
--user <Red Hat username>:<Red Hat password>
"https://sso.redhat.com/auth/realms/rhcc/protocol/redhat-docker-v2/auth?service=docker-registry&client_id=curl&scope=repository:rhel:pull"
-v

If the login fails, the following should be returned.

< HTTP/1.1 401 Unauthorized

If the login is successful, the following should be returned.

< HTTP/1.1 200 OK

The podman login command can be used to sign into registry.redhat.io. 

AVOID TROUBLE

If "cannot clone: Invalid argument" is returned and you are not using sudo, try including sudo.

~]$ sudo podman login registry.redhat.io
Username:
Password: 
Login Succeeded!

Optionally, the -u or --username and -p or --password options can be included.

~]$ sudo podman login --username john.doe registry.redhat.io
Login Succeeded!