No users available (typing a password errors with pam_authenticate: USER_UNKNOWN)

[sondrej]

I've enabled cosmic-greeter using systemctl enable cosmic-greeter.service, but there is no users to select, (the dropdown when clicking users icon is just a thin horizontal line). Entering the password for my user, or any random password just result in the error pam_authenticate: USER_UNKNOWN. So obviously there is no user selected.

I've tried to figure out the problem looking at PAM and greetd configs, but it seems to be correct AFAICT.
Looking at the info from systemctl show cosmic-greeter.service it runs greetd with --config /etc/greetd/cosmic-greeter.toml, this file exists and looks correct to me.
I've not done any changes to the configs other than creating the file /etc/pam.d/cosmic-greeter with the following content:

#%PAM-1.0
auth        include    login
account     include    login
session     include    login
password    include    login

which is the same as my Lemurs config (a terminal greeter).

Not sure if this is a bug or user error, in any case, thanks for any help resolving this.

Os: Arch Linux
Kernel: 6.13.0-rc3-1-mainline