Error creating customer account on prestashop

if you cant create account on prestashop, and you see this error message :

How to fix that error on your prestashop ?

modified AJAX request in file so it directs same place as form.
In /themes/default/authentication.tpl about line 97 there was line:

url: baseUri,
changed it to:

url: baseUri + 'index.php?controller=authentication',