The CloudLinux OS is installed on the server.
Unable to open file in Plesk > Domains > example.com > File Manager with the error below:
PLESK_ERROR: Unable to display the file /var/www/vhosts/example.com/index.html: Unable to read the file due to insufficient permissions
In an attempt to rename/move/remove a file in Domains > example.com > File Manager the following is shown:
PLESK_ERROR: Unable to rename /httpdocs/somefile: filemng failed: filemng: Error occured during /usr/bin/file command: No child processes System error 10:
No child process
The similar error can be found in
Misconfiguration in CageFS.
Go to Extensions > My Extensions > CageFS > Open.
Disable the subscription system user (and additional user if it exists) by moving it to Disabled form:
Note: in the current example, the subscription system user of
example.comdomain is johndoe.
Enable the subscription system user back by moving it to Enabled form: