Twitter API returns error 215, Bad Authentication Data
I am trying to call following Twitter's API to get a list of followers for a user.
http://api.twitter.com/1.1/followers/ids.json?cursor=-1&screen_name=username
And I am getting this error message in response.
{
code = 215;
message = "Bad Authentication data";
}
I can't seem to find the documentation related to this error code. Anyone has any idea about this error?