pictures was rejected due to technical issues

What kind of camera are you using?

Hello,

Unfortunately, the overall quality isn't good. It looks as if it had been taken with a smartphone, generally, the quality of the smartphone isn't so good for enlarging. Your photos show pixels when zoomed in as @reedesign1912 pointed out - you have JPEG compression artifacts. The phone has compressed the file to save space - the result - the file dosen't enlarge well. It is seen in all the photos.😒 And then you have the overall composition.

Have a read of this from Adobe about how to create better photos:
https://helpx.adobe.com/stock/how-to/tips-stock-image-acceptance.html?set=stock--fundamentals--adobe-stock-contributor

Photo 1: Not level. Overblown highlights.  Not in focus. Too noisy.

Photo 2: Not focused. Sign must be removed or cropped out.

Photo 3. Not level. Not focused.

All of your photos seem to have exposure issues (overexposed with blown out highlights.)  None of them seem to have a sharp focus.  When you look at the photo at 100% magnification you can see the images are quite pixelated.  Perhaps in post processing the photos were over sharpened.   See section of your photo below at 100%.

Also, you need to ensure the horizons in your photos are level - each of the photos seems to be off by a couple of degrees.

It would be worthwhile to read through Adobe stock requirements.

https://helpx.adobe.com/stock/contributor/help/photography-illustrations.html