I upgraded from Xubuntu 16.04->18.04 and then 18.04->20.04.1 I get this same behavior when laptop lid is closed and re-opened for new session. I've temporarily disabled 'Enable Lock Screen' under the Screensaver Preferences screen as a work around for now. See attached snippet from my journal log (removing irrelevant entries)..
I do not have xscreensaver installed but light-locker binary is present. ** Attachment added: "journal log output" https://bugs.launchpad.net/xfce4-screensaver/+bug/1875025/+attachment/5401218/+files/launchpad-1875025.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1875025 Title: Cannot enter password to unlock session To manage notifications about this bug go to: https://bugs.launchpad.net/xfce4-screensaver/+bug/1875025/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs