one or more technical issues

Well, judging from a photographic point of view, you could adjust the colour temp giving you this:

But do wonder if illustrations should be judged by the same criteria as in photographs, as this can be a matter of taste.

Though perhaps the moderator didn't like the purplish colour and saw it as a colour cast.

Hi Victor Almeida, I am an illustrator and have created pictures like this one. I do this for my own work but never for Adobe Stock. It looks as though you might have adjusted the curves in Photoshop to give the coloring and the look of lumination and halo but this is not usually wanted for stock. A buyer can adjust curves and get the various colors they want. If you just send the first drawing with no after effects it is more likely to get accepted. It might seem not as much fun for us but that is how things are with selling to stock. Maybe take the color back to an even variation of a softer color and lessen the strength of the dark areas.

It took me about five rejections to understand that we must keep our offerings simple .... Best regards, JH