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The web server should be configured to deliver content over HTTPS (via TLS/SSL).
In some instances Registry PHP code will inspect the PHP $_SERVER array to construct self-referential URLs. It is recommended that the Apache configuration directives UseCanonicalName and UseCanonicalPhysicalPort be set to On and that ServerName be properly configured with both hostname and port.
Make sure the server is capable of rendering PHP. On Linux systems most often the installation of PHP enables the php5_module but you should confirm it has been enabled. The configuration of Apache to use the module and parse .php files as PHP is also often done when PHP is installed but you should confirm that your Apache configuration contains lines similar to these:
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