From time to time the token from smqueue to Twitter may get broken when the API has a problem.
To fix this, sign into your Twitter profile first, then go to your smqueue Accounts Settings and re-authorize the Twitter Profile which is not sending out content.
To test if this is fixed, send a post by using the "Send Now" option located within the smqueue compose box.
After you send it, check "Analytics" and you should see the sent post.
If this is not the case please file a support ticket by sending an email to - firstname.lastname@example.org
For more information on how to re-authorize, see our topic: How to Re-Authorize a Social Media Profile.