Rejected Item

Hello guys!
I have just been rejected for some reason and I have no clue what is wrong with my mix. I am totally confused and dont know where to move. I hope some one can help me to understand logic of the reviewer. Thanks!
My track

Hello,
I liked your track. Maybe it sounds a bit empty. It’s an orchestral track, but there is just low strings and rhythm behind the melody. Maybe there shouldn’t exist an empty space between the melody and the background. Try to fulfill your track by other instruments.

TBH it sounds okay to me as I have heard worse on here that obviously have been approved. I think the lead instrument (guitar or piano) in the middle has grace notes that should be removed as they come across badly but I like the slur on the instruments. The drums and percussion could have been more epic and the ending more climatic but like I said at the start it sounds okay to me. Oh well it cannot be resubmitted but there is enough of an idea in this to overhaul it into a new track.