We introduced a bug into SongKong 4.3 that meant it wasn’t closing its connections to its internal database properly and this meant it could run out of database connections and then hang in some circumstances.
We have been working over this weekend to get this resolved, and now fixed in this new SongKong 4.4 release
http://blog.jthink.net/2016/12/songkong-44-released-decemeber-19th-2016.html