Rejected - technical issues ...why?

Stock doesn't typically accept B&W images.

• https://helpx.adobe.com/stock/contributor/help/reasons-for-content-rejection.html
• https://helpx.adobe.com/stock/contributor/help/quality-and-technical-issues.html
• https://helpx.adobe.com/stock/contributor/user-guide.html/stock/contributor/help/photography-illustrations.ug.html
• https://helpx.adobe.com/stock/how-to/tips-stock-image-acceptance.html

What program did you use to make this? if its Photo Shop then its not a true vector. If its in Illustrator then maybe the inspectors don't like the transparency you used.

But then I don't know what your tech issues are since you didn't give much details.

I can't tell if this is an image or a vector, but the edges are jagged when zooming in on the details.  There is also a slight moire pattern on it but I'm not sure that alone would be the culprit.