Why does Heroku fail to detect Node.js buildpack?
<p>I git cloned a Node.js application (the version specified in the <code>package.json</code> being <code>4.1.2</code> and that of my local machine being <code>6.2.2</code>) and tried to  git push on Heroku. But it failed to build and gave this error:</p>

<blockquote>
  <p>Failed to detect set buildpack https://codon-buildpacks.s3.amazonaws&period;com/buildpacks/heroku/nodejs.tgz</p>
</blockquote>

<p>Now I set the buildpack to heroku/nodejs and I get this message:</p>

<pre><code>Buildpack set. Next release on lit-badlands-92088 will use heroku/nodejs.
Run git push heroku master to create a new release using this buildpack.
</code></pre>

<p>Now when I run <code>git push heroku master</code>, I am again told:</p>

<pre><code>remote: -----&gt; Failed to detect set buildpack
        https://codon-buildpacks.s3.amazonaws.com/buildpacks/heroku/nodejs.tgz  

remote: More info: 
https://devcenter.heroku.com/articles/buildpacks#detection-failure  

remote:  
remote:  !     Push failed  
remote: Verifying deploy...  
remote:  
remote: !       Push rejected to lit-badlands-92088.
</code></pre>

<p>What could be the possible reasons for the Node.js buildpack not being detected even if I set it?</p>