Rejection due to quality Issues

We always need to see the rejected assets here, at full size as originally submitted. It only takes one error to result in a rejection, and we can usually locate one or more.

Quality comprises much more than just file size and resolution. Some of those quality criteria are stated in the rejection explanation that you received: "Common issues that can impact the technical quality of images include exposure issues, soft focus, excessive filtering or artifacts/noise. Learn more about our technical requirements here."

Some of my files are rejected due to quality issues. All my images are around 8k so i belive quality is not the issue

By @PNG Store

Well, if they got rejected for quality issues, the chances are high that there are quality issues. Again and again, as I have often stated here, the asset's resolution is not a quality mark. 

If you want a hint, why your asset has been refused, you should publish the asset here, in the same quality and resolution as submitted. Do no downscale, add watermarks or anything else. 

If you are new to stock, you should consider these resources: https://helpx.adobe.com/stock/contributor/tutorials.html
Please read the contributor user manual for more information on Adobe stock contributions: https://helpx.adobe.com/stock/contributor/user-guide.html
See here for rejection reasons: https://helpx.adobe.com/stock/contributor/help/reasons-for-content-rejection.html
and especially quality and technical issues: https://helpx.adobe.com/stock/contributor/help/quality-and-technical-issues.html

Some examples in high resolution would be helpful