title: ADB more than one device/emulator but there isn't
body: <pre><code>(master) $ adb -s emulator-5554 reverse tcp:8081 tcp:8081
  error: more than one device/emulator
  (master) $ adb devices -l
  List of devices attached
  emulator-5554          device product:sdk_gphone_x86 model:Android_SDK_built_for_x86 device:generic_x86 transport_id:2
  </code></pre>
  
  <p>Trying to deploy a react-native app to an emulated device. The build, gradle etc runs fine but when trying to connect to the emulator it shows an error <code>more than one device/emulator</code> despite there only being one device when running <code>adb devices</code></p>
  
  <p>Literally no idea how to solve this, Android Studio 3.1, emulated device is a Nexus 5x running Android 8. Have restarted, upgraded etc but still get this message.</p>