The fisrt time add the product to the ajax cart

[LowHighWeb]

Hi,

 

I have a problem with the ajax cart on prestashop 1.3.7.

I have the problem on all the browsers.

 

My ajax cart doesn't work when I click for the first time on the product, I have an error on the screen :

 

TECHNICAL ERROR: unable to add the product.

Details:

Error thrown: [object XMLHttpRequest]

Text status: parsererror

 

 

but it works when I click an another time on the same product.

 

 

It doesn't work on all pages of my site (page product and page category).

 

The product is add to the cart but the cart doesn't refresh when i have the error.

 

 

Thanks for you help.