Xcode 8 Beta (null) was unable to service the request

Question

I have an app that worked fine in the released version of Xcode. I downloaded the beta and after I fixed all the little changes I ran it and it worked. I just came back and

Answer 1

After reading @Droppy suggestion I read the thread and it is a common issue. To solve it is as follows

Problem solved for by an Apple Engineer in the lab. It's an issue they're working on. The bottom line was that when I copied Xcode to Applications folder, there was a bit set on it and that was preventing it from communicating with the simulator.

To fix it: Copy-paste Xcode-beta.app from Applications folder to somewhere else, e.g. Documents folder. Delete Xcode-beta.app from Applications folder. Move Xcode-beta.app from Documents to Applications folder again.

Seen here https://forums.developer.apple.com/message/143094#143094