title: CLI 400 error deploying to Google App Engine
body: <p>Today I got a new error when trying to deploy my application to Google App Engine via the command line:</p>
  
  <pre><code>Updating module [default]...-ERROR: (gcloud.preview.app.deploy) Server responded with code [400]:
    Bad Request Unexpected HTTP status 400.
    Your app may not have more than 120 versions.
    Please delete one of the existing versions before trying to create a new version.
  </code></pre>
  
  <p>I am deploying to the top level using <code>--promote</code>, not creating other versions. How do I fix this error?</p>