React Native on Ipad - Error - could not connect to development server
On your AppDelegate.m you have to update the jsCodeLocation and replace localhost with your machine ip address.
Either that or bundle the compiled source into your application, which is commented as option 2 on AppDelegate.m as well. You download the compiled code, and add it to your Xcode project.
Try to take a look here for the solution:
https://github.com/facebook/react-native/issues/240#issuecomment-86977126
Another potential issue which can cause the exact same error is App Transport Security (ATS) in iOS9--this happened to me, even though everything else was set up correctly. See my description and solution at https://stackoverflow.com/a/34880394/2397068.