pointing manually to the public_html/index.php gets aNot Found
The requested URL /index.php was not found on this server.
This was also happening to me from one particular client, but not other machines, and I soon identified the issue with the client having a proxy setup on the client machines (http=127.0.0.1:8082;https=127.0.0.1:8082 for something else) which, when attempting to login to the CWP panel
https://example.com:2031 or :2087, caused the "hijack".
Summary: be sure there are not proxies on the client machine (with the browser) connecting to the CWP /Centos server