Cant upload

You're not having trouble uploading.  Your work is being rejected during the review process.   Adobe Stock looks for highest visual and technical quality. See links below.
https://helpx.adobe.com/stock/contributor/help/reasons-for-content-rejection.html
https://helpx.adobe.com/stock/contributor/help/quality-and-technical-issues.html

Stock have millions of sunsets/sunrises by very talented contributors.  To be accepted in these fiercely competitive categories, your work must be outstanding.

The "technical issues" message means your image is not technically perfect, made to the highest professional standards and suitable for a multimillion dollar advertising campaign. It may be the editing, or it may be the camera, or the composition. It may be the settings you used in the camera. It may even be that you left in a signature. If you would like expert comment, please share a picture.

Without seeing an example image, nobody can answer you. But here you will find helpful tips: https://helpx.adobe.com/stock/contributor/help/quality-and-technical-issues.html

Please post your question with images in this forum: https://community.adobe.com/t5/stock-contributors/bd-p/Stock-Contributors?page=1&sort=latest_replies&filter=all