What could be causing the PHP session problem on the PC but not on the Android phone?

The PHP session problem on the PC but not on the Android phone could be caused by differences in the way sessions are handled by the browsers or operating systems. To solve this issue, you can try setting the session cookie parameters explicitly in your PHP code to ensure consistency across different devices.

// Set session cookie parameters
session_set_cookie_params(0, '/', '.yourdomain.com', false, true);

// Start the session
session_start();