Direct messages doesn ́t work via Twinkle to Twitter

2 days ago suddenly the following problem came up: all direct messages sent via twinkle don ́t reach the addressee and don ́t sync with twitter.
i re-installed the application, have chosen a different user name (twinkle) but the problem still exists.
public messages are shown perfectly in the twitter timeline.
an what confuses me completly: adding the command "d username_of_the_addressee" to a PUBLIC message in twinkle turns it into a direct message (blue background) -as expected- and syncs the message with twitter_direct_messages and let ́s the addressee the message!
any ideas what ́s going on with my account?