SUMMARY Without any input, the KDE Lock screen attempts to unlock the computer repeatedly, preventing the ability to input the password. It notifies you that unlocking failed, and then repeats this endlessly. Even with all input devices unplugged after the prompt is presented, this continues. STEPS TO REPRODUCE 1. Lock the computer. (Meta + L) 2. Trigger the login prompt. OBSERVED RESULT The prompt immediately notifies the user 'Unlocking failed' and will continue to do this immediately after the brief timeout. EXPECTED RESULT The prompt waits for the user to input the correct password and submit it to unlock the desktop. SOFTWARE/OS VERSIONS Arch Linux 6.18.2-arch2-1 KDE Plasma Version: 6.5.4 KDE Frameworks Version: 6.21.0 Qt Version: 6.10.1 ADDITIONAL INFORMATION Checking the KWin debug console, there is no stuck keys or stuck input that appears. I'm not sure what else to provide, please let me know what I can do to get you the information needed to further trace the problem. This also does not appear to be a new issue as per this topic https://discuss.kde.org/t/resolved-plasma-6-lock-screen-repeatedly-shakes-and-says-unlocking-failed/13754
pam.d misconfiguration pertaining to a user not being in a group and auto-failing no matter what when the user is not in that group.