Images are not accepted, writes technical problems

Sorry for the late answer. I hope you have found out by now on your own. But for others looking at this thread:

Technical problems is not linked to the subject of your picture but to the quality of the picture. Any defects, like out of focus, artifacts, washed out colours, missing contrast, noise, over- or under-exposure will trigger a "Technical issue" problem.

Your cat image: You have doctored the background, and did not cut out the fur correctly. Just to say: doing that is very time consuming, I don't do that for stock as it is not worth the effort. I try to get the background right. In addition there is a colour noise problem:

Second and third picture are oversharpened. You see a white halo around any objects, coming from the sharpening. There is also noise in the blue sky. The third picture also has a white balance problem. In addition for both pictures, the composition is bad. 

The flint picture is over sharpened. Otherwise it could be a nice picture.

The last picture has washed out colours, besides a white balance problem and is really badly composed. in the left upper corner the picture is blown out. It is genarally oversaturated.

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