Hello, buddy. So, Pixeljoint has an interesting tool for image inspection where you can use the URL of your art to analyze them. Here is the link of this piece:
https://www.linneart.com/pj/?input=https%3A%2F%2Fpixeljoint.com%2Fpixelart%2F161259.htm
I am not a mod or something, but there is a chance they do not approve your art because is being used a lot of colors (56~57).
Another thing: the submitted pixel arts should not be resized (for example, in the same resolution for social medias) and this is. If you resize it to 25% of the current size, all pixels will be preserved (because right now 1 visual pixels is actually 9).
As I said, I am not the one who approve or disapprove arts, but probably you're gonna have some issues with it. So I recommend: resize to 96 by 96 and decrease the number of colors used by using similar colors that is already being used. Good luck! 
Yes I confirm. The piece is upscalled and has too many colours. We accept only 1:1 pieces, and this one looks like around 16 colours. Everything else should be unified.