title: com.android.ddmlib.InstallException: Unable to upload some APKs?
body: <p>When I run "./gradlew installDebug" in android project I got the error </p>
  
  <pre><code>07:18:34 E/1834104550: Error while uploading app-debug.apk : Unknown failure
  Unable to install /Users/yejianfeng/Documents/baichebao/reactclient/android/app/build/outputs/apk/app-debug.apk
  com.android.ddmlib.InstallException: Unable to upload some APKs
  </code></pre>
  
  <p>and I have devices:</p>
  
  <pre><code>➜  android git:(master) ✗ adb devices;
  List of devices attached
  N7M6R15623003617    device
  </code></pre>
  
  <p>what can i do to fix this issue?</p>