What behaviour do you see when you try to log in through the GUI?
What are you seeing in /var/log/auth.log?
I usually use realmd and sssd to handle the configuration of clients, so my overall process is slightly different to what you are doing. But the additional steps I take are as follows.
Create /etc/lightdm/lightdm.conf.d/50-manual-login.conf:
[Seat:*]
greeter-hide-users=true
greeter-show-manual-login=true
Edit /etc/security/group.conf to specify what local groups domain users should be added to during a session. Example:
*;*;*;Al0000-2400;cdrom,dip,plugdev,lpadmin
Create /usr/share/pam-configs/groups-ldap with the following content:
(File must NOT have a trailing blank line)
Name: Activate /etc/security/group.conf
Default: no
Priority: 900
Auth-Type: Primary
Auth:
required pam_group.so use_first_pass
Enable the group settings and creation of the user's home directory on login:
$ sudo pam-auth-update
Make sure the following are enabled (do not disable others):
Activate /etc/security/group.conf
Create home directory on login