I checked the page and it seems that the web page on demoadminmes.epizy.com is making AJAX requests to demorunmestest.epizy.com.
This will not work, regardless of whether it’s intentional or not. This security system makes it impossible. Please move the API to the same domain as the website itself.
That’s because the URLs are pushed with a Javascript framework if you navigate to them from the home page. But you need .htaccess rules if you want direct links to work.
I once wrote this which may work for you too:
But you could also check the documentation of the web framework you’re using. Perhaps they have example .htaccess rules that work better for you.