title: ERROR An error occurred while running subprocess cordova
body: <p>I have finished a project, and I would like to build an apk. I have tried to build it, but after writing the sentences to build it, the third code gave me an error. 
  Here the code or sentences I wrote to be built it.</p>
  
  <pre><code>ionic cordova platform remove android
  ionic cordova plarform add android@6.4.0
  ionic cordova build android
  </code></pre>
  
  <p>I have built a project 3 day ago following the code I wrode above. Here the error. ( this time I connect with firebase)</p>
  
  <pre><code>Platform android already added.
  [ERROR] An error occurred while running subprocess cordova.
  
          cordova platform add android@6.4.0 --save exited with exit code 1.
  
          Re-running this command with the --verbose flag may provide more information.
  
  E:\ionic\notasFirebase&gt;ionic cordova build android
  &gt; ionic-app-scripts build --target cordova --platform android
  [19:08:57]  ionic-app-scripts 3.2.0
  [19:08:57]  build dev started ...
  [19:08:57]  clean started ...
  [19:08:57]  clean finished in 13 ms
  [19:08:57]  copy started ...
  [19:08:57]  deeplinks started ...
  [19:08:57]  deeplinks finished in 61 ms
  [19:08:57]  transpile started ...
  [19:09:03]  transpile finished in 6.09 s
  [19:09:03]  preprocess started ...
  [19:09:03]  preprocess finished in 1 ms
  [19:09:03]  webpack started ...
  [19:09:03]  copy finished in 6.41 s
  [19:09:11]  webpack finished in 8.34 s
  [19:09:11]  sass started ...
  [19:09:13]  sass finished in 1.66 s
  [19:09:13]  postprocess started ...
  [19:09:13]  postprocess finished in 29 ms
  [19:09:13]  lint started ...
  [19:09:13]  build dev finished in 16.44 s
  [19:09:19]  lint finished in 6.02 s
  &gt; cordova build android
  Unable to load PlatformApi from platform. Error: Cannot find module 'E:\ionic\notasFirebase\platforms\android\cordova\Api.js'
  Unhandled error. (The platform "android" does not appear to be a valid cordova platform. It is missing API.js. android not supported.)
  </code></pre>