well @paliblete there’s a lot of thing you have to understand before you submit a track into your portfolio and a lot of criterias that you have to keep in mind.
First: your music sounds like is an experimental music, something that does not match with the music that you can sell on @audiojungle you must listen very carefully the music that is allready on and take note of all the instruments, chords, melodys that authors are using regarding the category and attributes of each track.
Second: you must improve your sound, mixing and mastering skills, the sound of the instruments seems to be very poor and you have to work on that, the tempo and the use of the integrated instruments are quite rare, I don’t know way but sounds like does not match one on other.
Third: although you have musical experience, you must push your self to make the music sounds more comercial type, something that people wants to buy and could be useful for videos, slide photos etc.
These are the most common reasons for a rejected track but they are not the main reason and we will never know for sure why a track is been rejected, but you have to start making this changes so your music could be pick for seelling.
Have a good one.