Suddenly stopped working on my Mac version 10.11.4 Beta (15E39d)

Things were going very well but suddently when I try to start it, I get the message:
Real Racing 2 is damaged and can’t be opened. Delete “Real Racing 2” and download it again from the App Store.
I have done this but the problem remains. Is there something else I can do?
Thanks!

Pinawa about Real Racing 2, v1.1.2