I just installed the dvwa shooting range environment. When troubleshooting, I executed the systemctl restart php-fpm command as the root user, and then reported this error:
[root@localhost ~]# systemctl restart php-fpm
** (pkttyagent:10946): WARNING **: 17:09:31.957: 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)
After referring to such a document, I found that it was caused by the loss of x permissions. Refer to the document link: https://blog.csdn.net/huangjin0507/article/details/51536454
Then I used this command:
[root@localhost ~]# chmod 755 /
After the modification, the problem disappeared, php can be restarted, and dvwa can be accessed successfully.
You can check this document. There are two solutions, which are quite good.