we receive a lot of business/corporate capability-themed animations and therefore we’re very strict when reviewing these kinds of projects. Because there is so much competition in this genre, we only accept projects that we feel provide exceptional design quality and execution. Unfortunately, this project does not meet our high standards for this kind of style.
Hi. I guess the reason for rejection is exactly what reviewer said above. Slideshows/Presentations is a very huge and competitive category and your work brings nothing new to the table, sorry. Transitions are not different from many other existing works already approved, and design in general has nothing that can make your project an outstanding item among all those that are for sale in the market already.
Keep working, don’t give up!
Good luck! 
Thank you very much
You’re welcome