I have a similar issue on Ubuntu 20.04 with 1.30.0-0ubuntu4~20.04.1. Sometimes I enter my password, the screen goes black and I have to log in another time. Once lightdm didn't start at all.
If such issues occur I have these entries in the journal:
Sep 12 20:03:10 marco-MS-5455 lightdm[1123]: pam_unix(lightdm:auth): Couldn't open /etc/securetty: No such file or directory
Sep 12 20:03:12 marco-MS-5455 lightdm[1055]: pam_unix(lightdm-greeter:session): session closed for user lightdm
Sep 12 20:03:12 marco-MS-5455 systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Sep 12 20:03:12 marco-MS-5455 systemd[1]: lightdm.service: Failed with result 'exit-code'.
Sep 12 20:03:13 marco-MS-5455 systemd[1]: lightdm.service: Scheduled restart job, restart counter is at 1.
I have a similar issue on Ubuntu 20.04 with 1.30.0- 0ubuntu4~ 20.04.1. Sometimes I enter my password, the screen goes black and I have to log in another time. Once lightdm didn't start at all.
If such issues occur I have these entries in the journal: lightdm: auth): Couldn't open /etc/securetty: No such file or directory lightdm- greeter: session) : session closed for user lightdm
Sep 12 20:03:10 marco-MS-5455 lightdm[1123]: pam_unix(
Sep 12 20:03:12 marco-MS-5455 lightdm[1055]: pam_unix(
Sep 12 20:03:12 marco-MS-5455 systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Sep 12 20:03:12 marco-MS-5455 systemd[1]: lightdm.service: Failed with result 'exit-code'.
Sep 12 20:03:13 marco-MS-5455 systemd[1]: lightdm.service: Scheduled restart job, restart counter is at 1.