Hmm.. I read in the docs:
“To upload media you should use the URI /api/user/username/uploads.
A POST request should be made to the media upload URI submitting at least two header:
- Content-Type - This being a valid mimetype for the media.
- Content-Length - size in bytes of the media.”
Dianara doesn't fill Content-Length, which seems to be mandatory here. But that doesn't seem related to the OAuth error. Hmm...