What are common issues that may cause Apache and PHP to not run properly together on a Linux system?

One common issue that may cause Apache and PHP to not run properly together on a Linux system is a misconfiguration of the PHP module in the Apache configuration file. This can result in PHP code not being executed by the server. To solve this issue, ensure that the PHP module is properly enabled in the Apache configuration file.

# Ensure that the PHP module is enabled in the Apache configuration file
LoadModule php7_module /usr/lib/apache2/modules/libphp7.so
AddHandler php7-script .php