Hard rejected. Please help to understand why.

I’ve got 3 of 3 hard rejects.

After completing our review, we’ve determined that ‘Elegy’ isn’t at the quality standard needed to continue forward with the review process on AudioJungle. As the submission is too far off the standards we require, you’ll be unable to re-submit on this occasion.
Comments from your Quality team
This submission does not meet our commercial production (mixing/mastering/sample quality) standard or our commercial composition/arrangement standard, unfortunately.

The tracks:

Can your please help me to understand issues of the tracks.
I’m newbie in mastering.
Can you please criticize my mastering, composition, used samples etc.

In my opinion, the tech quality of the tracks needs improvements.
In the second and the third tracks there is a clear clipping. It should be avoided in any case.

Hi, Antonio!
Thank you so much.