User/lookup or user/show returning 404


Hi all,

I have this strange issue: all the time I look for a user (lookup or show and id or screen_name doesn’t change the problem) I receive the 404 error.
I am sure the users I am looking for exist, because I tried other functions (for example, fetching their tweets works fine), and I tried even to look at my same profile, getting a 404 again.

What’s wrong?