Same problem, I was able to use the GKLeaderboard.submitScores class function, but it only worked the first time. I can't post new scores and there is no error.

I am using MKLocalPointsOfInterestRequest which takes a central point and radius (or a region) to find places of interest within this boundary. It seems, as written in the documentation, written specifically for this purpose. Yet I get the MKErrorDomain code=4 as well, either when run on a simulator or run on an actual device. As a test, I fed it the coordinates of landmark, expecting it to at least return that. Kind of disappointing.