I'm new to adobe stock and didn't understand why these photos were occluded for technical reasons. Tell me please
Bad framing, missing contrast, slightly out of focus, underexposed. Your first picture is also not level. And I would add that the white balance is not correct, but that one is more difficult to see because of the missing reference.
For the exposure, you may look at the histogram:
You see that half of the whites are missing.
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
Food photography can be very challenging. At a minimum, you need a tripod, multiple light sources and reflectors.
All food and especially cakes must have an appetizing appearance -- pleasing color, good light, focus and composition. Cake images should evoke feelings of "yum, that looks delicious!"
Also whoever designed these cakes (edible or fake) will need to sign a property release giving you and Adobe permission to sell images of their "artwork" commercially.
Read the Adobe Stock Contributor User Guide:
See what other Stock Contributors are doing in this category. It sometimes helps to see what your competition is doing.