I used Chrome’s Dev Tools and I get this errors:
GET https://laenciclopediagalactica.info/wp-includes/js/tinymce/wp-tinymce.php?c=1&ver=349-21274 404 (Not Found) post-new.php:1127
Uncaught ReferenceError: tinyMCE is not defined post-new.php:1129
(anonymous function) post-new.php:1129
Uncaught ReferenceError: tinyMCE is not defined post-new.php:1171
(anonymous function) post-new.php:1171
I downloaded a fresh WP and uploaded tinyMCE, but I got the same error.
Also, I tried the en.js trick and still no joy.