From a fresh updated system run:
gdbus call -e -d com.canonical.indicator.session -o /com/canonical/indicator/session -m org.gtk.Actions.Activate "switch-to-greeter" "[]" "{}"
It will switch to greeter, login and then lock the screen (Ctrl+Alt+L). Does the lock-screen show the "Authentication Error" ?
From a fresh updated system run:
gdbus call -e -d com.canonical. indicator. session -o /com/canonical/ indicator/ session -m org.gtk. Actions. Activate "switch-to-greeter" "[]" "{}"
It will switch to greeter, login and then lock the screen (Ctrl+Alt+L). Does the lock-screen show the "Authentication Error" ?