I installed this recently, I didn't think it was working and am not techie enough to troubleshoot, so i thought oh well, never mind.
I had set it up while a song was paused in Musicbee and when I hit play nothing would happen (though I think the generic "Musicbee" was showing on my TV). But then when that song stopped, and another started I had music coming out of my sound bar (into which my Cromecast is plugged)! Happy days! So it won't start playing until a track is STOPPED and a new one begins.
Though it can't play gapless, it's like it disconnects and reconnects between each song, so if I have my PC speakers on at the same time, they play the very start of the song 2 or 3 times before it starts playing on the soundbar.