Some time ago, SecondHandSongs (https://secondhandsongs.com/) enabled HTTPS and dropped the "www" from their address. There are lots (probably in the hundreds or thousands) of SecondHandSongs links in the database using the old link format.

Example old-style URL: http://www.secondhandsongs.com/work/18463

Example new-style URL (the old URLs redirect like this): https://secondhandsongs.com/work/18463