Thanks,
Peter.
Make sure that any instances of autologin in /etc/lightdm/lightdm.conf are commmented out with a "#".
Thanks for the pointer. What helped was to UNCOMMENT the following lines:
pam-service=lightdm
pam-autologin-service=lightdm-autologin
autologin-user=<your-user-name>
autologin-user-timeout=0
Thank you!
Peter.