File rejected due to technical issues

Hi! Could you please help me to understand what is wrong with the file? It's a mov animation with transparent background in which a cup slide in and out. The file was rejected due to technical issues:

"Unfortunately, during our review we found that it contains one or more technical issues, such as unintentional shaking, empty black or white frame, compression and/or audio issues, so we can't accept it into our collection."

Thanks a lot!