This section will introduce some basic and general trouble shooting tips in the event you encounter issues with PrestaShop, such as blank page, "Internal Server Error", or "Fatal Error".

 
1. Check this first

Pleae check that folder and file access permissions are set correctly on your server. Recommended settings are as follows:

- For all folders, set permission to 755

- For all files, set permission to 644

Some customers set folder permission to 777, which means a public user has full permissions.  This can work, but may cause errors on some servers, depending on things such as hosting environment - e.g. Linux or Windows?

2. Turn error messages on

Set 'display_errors' to 'on,' and SQL_DEBUG to true in the file YourStoreRoot/config/config.inc.php.

You will find the following two lines at the top of this file:

@ini_set('display_errors', 'on');
define('_PS_DEBUG_SQL_', true);

After changing these lines and saving the file, load the page again that was causing an issue. You should now be able to see errors displayed on the page. Usually at top of the page, but it could be at any location of the page.

The error message displayed sholuld help you identify the source of the issue, and whether it is a PrestaShop core page or a module.  Please note, however, the error source does not necessarily mean it is really the cause of the problem. The actual cause of the problem could be somewhere else.  It will, though, at least give you a general direction to look for the source of the problem.

 3. Set break point.

Assuming you are not PHP developer, here is a tip we use frequently when working on a client's site and we encounter a fatal error:

This tip is usful when you encounter an "Internal Server Error", or "Fatal Error", but there are no detailed error messages.  Even though you have turned the debug information disiplay option on, you still cannot see any detailed message.

Add the following line in the page the top of the page right after "<?php", then refresh you page again.

die("Break point here");

If you see the following message on your page:

Break point here

It means the problem is being caused by a PrestaShop page script in the line directly after that.  Move the die("Break point here") line a few lines downward and repeat the above step until you see the original error message you saw originally.

 If you do not see the "Break point here", even when you've added this line on the top line of the PHP page, it means the issue is not being caused by the page script.  Instead, it is configuration related issue.

By performing these steps, you should be able to identify the location in the file that is causing the issue.