I'm using the common method for backing track when going live, with the click going to my drummer using the hard panned left (click + backing track) and right (backing track only). Before setting anything up, I made sure that the 2 tracks above are in Mono and panned them appropriately. Here's how I set it all up, Laptop --- Steinberg CI1 ---
[Output 1 (Backing track only) - FOH] [Output 2 (Backing track w/ click) - Drummer's IEM] The problem I'm having is that the track comes out nicely to the FOH but my drummer's only hearing the right side of it. Surprisingly, I've already had the track in Mono as well as running the IEM's cable (Stereo end) to a Stereo to Mono adapter below :

What am I doing wrong? Many thanks in advance.