I uploaded some wallpapers 4k or UHD

i received email for all my creations with following context: We have completed our review … and unfortunately we found it isn’t at the quality standard required to move forward, and you won’t be able to re-submit this item again.
I uploaded some minimalist wallpapers with hight -quality.
what i did wrong?

That means that the items are designed in a way that don’t meet the quality standards. You can post what they look like here, and we can give you some feedback.

hi pls show us the concerned item, otherwise , hard to help u in any way … if u do we will provide u with some advice to take your item to the next level

Alright, well not only do people very rarely spend money on a wallpaper, I don’t think this is worth buying as a wallpaper. You need to have something truely incredible to sell something as a wallpaper, especially at $1 or more.

In terms of the illustration itself, there are too many shaky lines, it doesn’t look professionally made. Try less saturated colours, and pay attention to the line and shape quality, especially with the rainbow vomit, I’d expect it to have a smooth arch, but it’s jagged. I think it’d also look a bit better if you had some shadows on the ground, that way it’d look like it actually fits within the image rather than just pasted on top of it.

Your best bet for something like this is to sell it under the Illustration category as a vector that people can use for whatever they want, but even then, I don’t think this is up to the quality standard needed for that.