title: Google Colaboratory: Timed out error
body: <p>Whenver I type any command in Colaboratory, I get following error:</p>
  
  <pre><code>Failed to execute cell. Could not send execute message to runtime: CustomError: Timed out waiting for promise
  </code></pre>
  
  <p>Why is this happening and what can I do to prevent it?</p>