Database error in vBulletin 3.7.3:

Invalid SQL:

SELECT thread.title, thread.prefixid, thread.threadid, thread.forumid, thread.postuserid, thread.visible
,post.pagetext AS preview
, NOT ISNULL(subscribethread.subscribethreadid) AS issubscribed
FROM thread AS thread
LEFT JOIN post AS post ON(post.postid = thread.firstpostid)
LEFT JOIN subscribethread AS subscribethread ON(subscribethread.threadid = thread.threadid AND subscribethread.userid = 3 AND canview = 1)
WHERE thread.threadid IN (0,10712,11406);

MySQL Error : MySQL server has gone away