The following errors may be encountered when attempting to start, stop, or restart a service.
Unable to register authentication agent: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: Cannot determine user of subject
Error registering authentication agent: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: Cannot determine user of subject (polkit-error-quark, 0)' when restarting a service.
This error is caused by a bug in the Polkit operating system package. When the
hidepid=2 option is used to mount
/proc, polkitd is unable to read the
/proc/<PID>/* information of the calling process. The issue started in polkit-0.112-18.el7 due to the hardening made to fix the security vulnerability reported in CVE-2018-1116.
- Access the server's command line as the 'root' user via SSH or "Terminal" in WHM.
- Run the following commands.
mount proc -o remount,hidepid=0
systemctl restart polkit.service