WatchOS 2 with Xcode 7 cannot run

When I try to run the watchkit app, it success, but didnt run at all, and I'm even not able to install the app on watch simulator. When I try to use my own phone and watch, it says: unknown errer happens.

Does anyone know how to solve this?

WatchOS 2 with Xcode 7 cannot run
 
 
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