2.14.9.12. Enable debug mode in PrestaShop

Open the site file config/defines.inc.php in the built-in editor of file manager or any FTP client.
Find the line with the parameter _PS_MODE_DEV_:
```
define('_PS_MODE_DEV_', false);
```
In the line you found, replace false with true and save your changes:
```
define('_PS_MODE_DEV_', true);
```
Reproduce the error on your site.

After finding the source of errors on your site and fixing them, you should disable debug mode.