I think the melody (from 0:14) is overcompressed. The arrangement is a bit confusing, listen to the top new tracks in this genre and do the same arrangement. It’s not stealing, almost everyone is using similar arrangements here.
As for the reason of rejection, you won’t get it from the reviewers, they’re just writing you an automatic standard message.
Here are some things I think might be the reason for the rejection:
-The piano melody sounds a little ‘mechanical’
-The strings sample (the one that comes in at 16 seconds for the first time) sounds out of place.
-Same goes for the cello that comes in around 50 seconds. It sounds like cheap string samples, not organic, natural enough.
These kinds of tracks have to be SPOT ON in terms of composition and audio quality. or else they tend to sound ‘cheap’.
You can tell if a piano melody is played by a pro, or constructed in a sequencer.