The Mudcat linkmaker - see Make a link ("blue clicky") below the Submit Message box at the bottom of the thread page - has this quirky thing where you have to remove the https://mudcat.org/ part of the address because that part is automatically added. I usually forget to do that and then one of the lovely Mudelves very kindly fixes my dodgy link.

Note: For non-Mudcat links the whole web address is pasted into the "Link URL:" box.

Well done, Guest, ottery for identifying the song.