Error message popped up saying failed to update system

Hi there,
This evening when I have opened my PC this message appeared on my desktop. I never ran an update to my system and now I am surprised that I am not able to do this. For my curiosity, why I can’t update my system ? What this error message means ?
Regards !

Failed to update system
The error was: org.freedesktop.packagekit.update- system auth_admin_keep_always
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