When the music stops it really takes away the flow of the instruments. The flow starts up again but then it just suddenly stops and that happens on and off throughout the song. I recommend taking some songs from Zelda The Ocarina of Time for inspiration. It seems like this song is something like those songs. Some of notes feel kinda bland or flat and the song really doesn't sound full. I think something like a violin, harp or bass might help to benefit the composition (help make everything work better together.)
Also to use your songs in GD you have to get scouted and then you have to get whitelisted. You have to earn a scout.
Overall there's a lot you could improve but don't worry. We all start somewhere and I think with enough learning and time you could make something really good!