Wierd, the forum search now appears to have a bug, where if you use a word that's too common, or too short, it doesnt' just ignore it (like it used to), or give a specific error about that term, it just fails to return any results at all.
Leaving "of" out:
https://endless-sphere.com/forums/search.php?keywords=Horses+Iron&terms=all&author=&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search