Apparently this is not a wide spread issue but I have the same issues, normally when my wife logs off of cafe world from facebook. Restarting mac seems to do the trick for me, for a day or two. But is very annoying I just want to blame it on facebook and their stupid apps and plugins. Although I do not know much, just looking for answers like yourself.
And what the hell is up with the error in window, cannot find host I have read so much and tried everything except reinstalling, never used to have these problems. UUURRRGGGHHH.