It’s not how taxonomy work. The apps_cat is just the taxonomy, not the term. Like category, you will receive not found with http://redesign.conei-sa.com/category. You must point to a specific term of apps_cat. apps_cat can’t have any post, only the term of it has.
Anyway, if you got not found with term page, try update permalink structure. Another tip for testing you can try is switching to default permalink while coding to make sure it work, then switch back to pretty permalink.