Why was my image rejected?

I could also be your rubles.
"Paper money must not be reproduced in whole but partial depictions (<75%) may be acceptable in some countries. All currency featuring the likeness of Queen Elizabeth II is unacceptable."

Hard to say for sure with the technical reason. The white balance feels a bit on the warm (orange) side to me. How are the noise levels when you view the full resolution file at 100%? I'm assuming you didn't submit this with your watermark on it. 

Unless this was an Illustrative Editorial file, you also have some intellectual property issues, specifically with the camera brand information on the front.

I wish you the best of the luck with your future uploads.

-Mat