why was this photo rejected

You need to post th full size image as submitted to stock. In addition you need to tell us the rejection reason, as given by Adobe. The heading is enough.

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

Too small to critique. In any case, there are millions of images of cats on Adobe Stock and submissions must be extremely unique to be accepted, while these look more like casual snapshots.