Gene Heskett composed on 2019-12-31 13:26 (UTC-0500):
Thanks for any help. debian stretch on amd64 if that helps.
1-Make sure tdm-trinity is installed and configured.
2-Purge lightdm, sddm, kdm, gdm and any other dm you can find besides tdm.
3-Make sure /etc/X11/default-display-manager exists and contains /opt/trinity/bin/tdm.