May you be + adjectives ( happy)
May you have/find/ be blessed with etc + noun ( happiness)
May I go out ?>For polite request.
Can I go out? > Its ok since we know what you mean .
But, I can also reply " Sure you can go out ,but you may not ( Can is an ability to do something , so going out is surely can be done by you ( but, you may not >meaning permission not given)