what is the reason of rejection?

It's underexposed and poorly composed - you shouldn't have cut off part of the plate.

It's too hard to tell why your image was rejected because the image you posted is so small.

However, the most common reasons for rejection are poor qualilty (out of focus), similar content, or intellectual property. 

If you select your image on Adobe Stock, on the right side there should be a brief explanation why it was rejected.

Too small. Post the original image as submitted.