Whats wrong?

Adobe Stock customers pay for high quality, full color images for use in commercial projects.  This is neither.

Read the DOs & DON'Ts in your Stock Contributor User Guide.  There is very good information there about what Stock expects from contributors.

• 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

Hope that helps.

Tell us the reason that Adobe gave you. The title is enough.

Quality issues: it's black and white. Check the requirements.

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

If you are a generative AI contributor, please look into these instructions and follow them by the letter: https://community.adobe.com/t5/stock-contributors-discussions/generative-ai-submission-guidelines/td-p/13549435