If you want to check out the eight songs to see if you can identify what the reason could be, they are all streaming on Spotify.
The two that were approved were 'I Want You' and 'Light in The Dark'.
I would recommend that you post at least two of them here. One that was approved and one that wasn't. Indicate which is which. Then it's easier to listen and give our thoughts. I don't like chasing all over the internet to try to find something.
Edit: I have had some of my music rejected by various individuals and organizations for various reasons. Mostly it had to do with the overall quality of the recording itself or in several of the rejections the comment was that the music sounded too fake and too midi or synthy.... and this was in reference to piano parts. They asked me to record the parts again with a "real piano" vs using something obviously midi/synth.
They don't have issues generally with quality sampled synths or midi unless you can listen and tell immediately that it's not real. A dead giveaway is the sound quality of the instrument just doesn't sound real as in using a cheap general midi piano voice.... or.... the velocity is all the same. In other words, there no touch sensitivity in the playing and no dynamics like a live player would incorporate into their playing. And obviously, everything is dead on the beat. Oh the humanity....!!!! or...lack thereof.