I would like to understand why only some photos are accepted and others receive "technical problems" feedback. I already have several photos approved and can be downloaded, but when I try to send photos of the same level it is not approved. I think this is limiting my portfolio.
Please post a rejected picture with the rejection reason at a resolution high enough to check the quality. When we have checked that picture and given you the correct clues as where to look, you can examine your remaining rejections.
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