I get same message recently. And as I took a better look on conditions, terms of submissions, basically, there could be plenty of things that your project could be rejected for, so it’s kind of confusing for new people to understand better what they are doing wrong without any hint about it.
I didn’t write to Tech Support, even if they left link to it, because I have several new projects waiting to be finished, so I’ll try to develop them to try again.
That suppose to be a Hard Rejection (as you could see in the forum a lot of topics on Hard or Soft rejections). 