Typesetter CMS white page or 500 error can be investigated by looking into Apache logs or setting php errors to be visible:

• Open gpconfig.php file and change php’s display_errors setting to 1.
• Taking XAMPP as an example, access Apache error log by navigating to C:\xampp\apache\logs and opening error.log

White page or 500 error during first installation – Most likely due to PHP version not happy with curly braces. If you are using PHP 8.2+ install Typesetter CMS 5.2. You can also downgrade php version and install 5.1.

Example of XAMPP working combo: Xampp 7.4.33 + Typesetter CMS 5.1.