You have bad lighting - shadows around the pizza, and some of it isn't in focus.
I agree with @ricky336: the lights could be better, especially to the right. A reflector would have made miracles here. And there is the missing sharpness especially again to the lower right.
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