Error 500 when clicking product on certain category

[kiccokeys]

Hello everyone,

i'm quite new here so forgive me in case of netiquette mistakes.

Here's the issue i have:

 

when clicking on a certain product category, i get error 500. (memory limit exceed).

Here's what i tried.

 

- matching a random product in that category with another category. Product works if clicking on it by other category;

- via database, replace that category association to all products that were in affected category, with a brand-new one (to do this i update ps_produtct, ps_product_shop and ps_product_category). Nothing happened, same error, so i restored backup.
- change memory limit to 1 Gb and then to -1.
- change max execution time to 60 sec.

 

Now on products of affected category i have this errors, randomly:

 

Fatal error: Maximum execution time of 60 seconds exceeded in /public_html/classes/Pack.php on line 119
.... /Pack.php on line 159

.... /Pack.php on line 155

.... /Pack.php on line 161

 

and 

 

.../classes/Configuration.php on line 179

 

Prestashop is 1.6.1.6.

Anyone had the same problem?

 

Thanks,