If you do not have access to the error logs of your server, you can display the error on the redirection page by doing the following:
- Disable the Instant Payment Notification URL in the Expert Back Office.
Reminder: to disable the IPN, go to Settings > Notification rules > Right-click on Instant Payment Notification URL at the end of payment > Disable the rule.
- Display the errors by activating the DEV mode for your PrestaShop store. To do so, in the defines.inc.php file located in the config folder, replace:
define('_PS_MODE_DEV_', false);
With: define('_PS_MODE_DEV_', true);
- Make a test payment and click on the return to shop button, your error should appear on the screen.
- Once the error appears, do not forget to disable the DEV mode for your PrestaShop store and to re-enable the Instant Payment Notification URL.