I started to get this error:
#0 /home/user/public_html/library/GFNCoders/XenSocialize/Helper/Fallback/FacebookBase.php(875): BaseFacebook->throwAPIException(Array)
#1 [internal function]: BaseFacebook->_graph('/10000453522829...', 'POST', Array)
#2 /home/user/public_html/library/GFNCoders/XenSocialize/Helper/Fallback/FacebookBase.php(649): call_user_func_array(Array, Array)
#3 /home/user/public_html/library/GFNCoders/XenSocialize/Helper/Facebook.php(45): BaseFacebook->api('/10000453522829...', 'POST', Array)
#4 /home/user/public_html/library/GFNCoders/XenSocialize/DataWriter/Extended/DiscussionThread.php(41): GFNCoders_XenSocialize_Helper_Facebook:
ostStatus(Array, Array)
#5 /home/user/public_html/library/XenForo/DataWriter/Discussion.php(391): GFNCoders_XenSocialize_DataWriter_Extended_DiscussionThread->_discussionPostSave(Array)
#6 /home/user/public_html/library/XenForo/DataWriter.php(1385): XenForo_DataWriter_Discussion->_postSave()
#7 /home/user/public_html/library/XenForo/ControllerPublic/Forum.php(490): XenForo_DataWriter->save()
#8 /home/user/public_html/library/TMDb/ControllerPublic/Forum.php(16): XenForo_ControllerPublic_Forum->actionAddThread()
#9 /home/user/public_html/library/Waindigo/PostAsUser/ControllerPublic/Forum.php(44): TMDb_ControllerPublic_Forum->actionAddThread()
#10 /home/user/public_html/library/Tinhte/XenTag/XenForo/ControllerPublic/Forum.php(23): Waindigo_PostAsUser_ControllerPublic_Forum->actionAddThread()
#11 /home/user/public_html/library/XenForo/FrontController.php(310): Tinhte_XenTag_XenForo_ControllerPublic_Forum->actionAddThread()
#12 /home/user/public_html/library/XenForo/FrontController.php(132): XenForo_FrontController->dispatch(Object(XenForo_RouteMatch))
#13 /home/user/public_html/index.php(13): XenForo_FrontController->run()
#14 {main}
FacebookApiException: Error validating access token: The session has been invalidated because the user has changed the password. - library/GFNCoders/XenSocialize/Helper/Fallback/FacebookBase.php:1249
When a user opens a thread it returns with a "requested thread not found" error.