Hello Manuel,
I am experiencing the same issues.
I can call https://api.twitter.com/1.1/account/verify_credentials.json as part of retrieving an OAuth token from Twitter without a problem.
If I then start to call some of the other endpoints, e.g.
api.twitter.com/1.1/users/show.json
(GET)
api.twitter.com/1.1/followers/ids.j
... (GET)
api.twitter.com/1.1/friends/ids.jso
... (GET)
api.twitter.com/1.1/blocks/ids.json
(GET)
I will get error Code 32 'Could not authenticate you'
If I set authorization_header to 0 then it will work, however even then if I call users/lookup.json via POST I get error Code 215 'Bad Authentication data'
This seems to be a Twitter specific issue as I use this class to connect to Facebook too without any issues.
Thanks
Stuart