title: Gmail - smtp error 421 4.7.0
body: <p>We are using <code>gmail oAuth2</code> to send the mail from <code>nodemailer</code> and receiving below error -</p>
  
  <pre><code>{"code":"EENVELOPE","response":"421 4.7.0 Temporary System Problem.  
  Try again later (WS). e189-v6sm98ioe.0 - 
  gsmtp","responseCode":421,"command":"DATA"}
  </code></pre>
  
  <p>Out testing team by mistake run the automation test script and triggered a lot of mails simultaneously, I understand that might have blocked the mail's temporarily as the error suggest. I am interested to know how long this blockage will continue and what can one do to resolve it. At this point it is not possible for us to switch mail sending from gmail to some thing else. </p>