empathy "Facebook account requires authorization" problem

Solution 1:

The telepathy-gabble 0.18.1 package in Ubuntu actually contained a work-around for the problem, not a proper solution. Quoting from the ChangeLog:

telepathy-gabble (0.18.1-1) unstable; urgency=low

  * New upstream stable release
    - work around Facebook server behaviour change so we don't consider its
      service discovery response to be spoofed (Closes: #721883)

 -- Simon McVittie  Mon, 09 Sep 2013 13:05:13 +0100

Apparently, this work-around does not work, and in fact the status of the bug has been reverted from Fix Released to Confirmed.

For the proper fix I'm sorry you will have to wait for the upstream bug to be fixed (unless someone proposes an another work-around in the meantime).