I have provisioned an apache webserver with a custom user for content management, created a http-docs root directory in /var/, and assigned ownership to the user with the usual chown stuff, yada yada yada, and basically the basic stuff works.
I've uploaded some content and it displays when accessing via HTTP & HTTPS.
What totally confuses me is that the PHP pages for managing my CMS do not display, whereas a web-shell does.
In case it is relevant I am using the Armadillo CMS that is available as a RapidWeaver plugin. It depends on Apache, PHP, and MySQL and all these requirements are (apparently) met. Furthermore I can exclude MySQL as being at fault since I need to access the admin/setup page in order to provision the system, and insofar as it keeps turning up blank, I have not been able to even attempt to configure it.
While inspecting the relevant .php file from within the server's filesystem the file is populated with valid PHP code.
What am I doing wrong? What have I forgotten to do?