After adding this to the info.plist of the Watchkit app:
<key>NSAppTransportSecurity</key>
<dict>
<key>NSAllowsArbitraryLoads</key>
<true/>
</dict>
I get the folloging when trying to get it to run on the simulator.
The operation couldn’t be completed. (LaunchServicesError error 0.)
I cleaned the build, reset all simulators and emptied the "Derived Build" folder. No avail.
Here is answer
WatchOS 2: "Cannot Install Watch App" "Error Launching 'TestApp WatchKit App Extension'"
Put this key in WatchOS extension info.plist instead of WatchOS App plist.