Posting an image using Tweepy failed - error code 32


I played a little with Tweepy and I found a strange behaviour for posting images:
The response from Twitter API is: “errors”:[{“message”:“Could not authenticate you”

I’ve already read all the realted discussions and nothing seems to help me. Also, I tried
from another computer and all worked ok.

Can you, please, give me an advice? It may be the auth package (I use requests-oauth).