What are common reasons for a session not being created or maintained properly in PHP?

Common reasons for a session not being created or maintained properly in PHP include incorrect session configuration, missing session_start() function call, or issues with session cookies. To solve this issue, make sure to call session_start() at the beginning of each PHP file that needs to access session data and ensure that session.save_path is correctly configured in php.ini.

// Correct way to start a session in PHP
session_start();