users/lookup seems not be working in the API console. For instance: I signed in, and selected my application in the console Headers and methods: GET / 1 / users/lookup Parameters and values: user_id / 0 Response body: ... "No user matches for specified terms" ...
The same for parameters and values: screen_name / twitterapi Interesting is maybe that I get a 404-error when using users/lookup in my own application. For your information: I do succesfully use OAuth, and other queries like friends/ids are doing fine.