UIApplication openUrl not working with formatted NSString

Question

I have the following code to open google maps:

NSString *urlString = [NSString stringWithFormat:@"http://maps.google.com/maps?q=%@, Anchorage, AK",addressString];
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:urlString]];

But it doesn't work and there is no error. It just doesn't open.