I know exactly because I cheated
Won't post it on here and spoil the game but this is the site I use whenever I need to look up anything with regards historic results/records etc.
https://www.11v11.com/teams/rotherham-united/
Our last league loss to them at NYS on Valentine's Day in 2017 featured in one of my Who Am I Quizzes but I've already forgotten how
Just looked it up, Semi's first goal for us https://boards.footymad.net/showthread.php?t=38259917