If you need to enable the error Reporting in Prestahsop. You need to follow below step.
- 1) GO to PrestaShop admin panel (Back office) >> go to Advanced Parameters >>> Performance and find Debug mode setting and set Debug mode to Yes.
- 2) Save to this section.
It is still possible to perform this change manually.
If you can't acces you dashboard you can also enable it through FTP by accessing config/defines.inc.php and usually @line 29 you will find :