Symptoms
When accessing your website you receive Error 500 Internal Server Error.
Description
The Apache error log /var/log/apache2/error_log shows the following :
[Wed Nov 25 09:59:19.922909 2020] [cgi:error] [pid 413437] [client 1.2.3.4:32833] AH01215: suexec policy violation: see suexec log for more details: /usr/local/cpanel/cgi-sys/ea-php72, referer: http://tld.com/
[Wed Nov 25 09:59:19.922936 2020] [cgi:error] [pid 413437] [client 1.2.3.4:32833] End of script output before headers: ea-php72, referer: http://tld.com/
Taking a closer look at the SuExec log at /etc/apache2/logs/suexec_log showed that the issue was an inability to run ea-php72:
[2020-11-25 10:00:05]: uid: (1005/username) gid: (1008/username) cmd: ea-php72
[2020-11-25 10:00:05]: cannot stat program: (ea-php72)
This is an issue with CageFS needing to be updated.
Workaround
Update CageFS skeleton using this command:
cagefsctl --force-update