Finally I’ve found the problem. In my wordpress I have the form inserted using the shortcode. But also I’m using SPOTS plugin, and the shortcode is inserted in one SPOT.
SPOTS has a view cache enabled by default. The form shortcode works perfectly when I’m logged (because the SPOTS cache is disabled when the editor is logged ?? ), but the process doesn’t work when the cache is enabled on not logged sessions because the SPOT cache save the form view but the requests to do_action for insert Ninja-forms JavaScript and CSS aren’t called.
Simply go to the configuration of SPOTS, and set 0 to cache.
If you have using another custom posts plugin, be carefull with the cache ??
