Root login is now by default disabled by /etc/cockpit/disallowed-users, so if you want to allow root login you will need to remove the root entry from that file.

[govwin]

          Root login is now by default disabled by `/etc/cockpit/disallowed-users`, so if you want to allow root login you will need to remove the `root` entry from that file.

Originally posted by @jelly in #18427 (comment)

This is an unnecessary interference.
Why not let it default to how the user has kept it. That is, if root is enabled in the system, let the root login on cockpit as well.

[jelly]

From our perspective allowing root login possibly public on the internet is a no-go, and if a user wants too they can by either removing the file or editing disallowed-users file. Note that on upgrading we respected the users existing configuration and didn't disable root logins.