title: smtplib.SMTPAuthenticationError: (535, '5.7.3 Authentication unsuccessful')
body: <p>I am trying to use smtplib for sending mails in python 2.7. The below code is pretty simple:</p>
  <pre><code>import smtplib
  
  def main(argv=None):
  
      sender = 'abc@gmail.com'
      receivers = ['xyz@gmail.com']      
  
      message = &quot;&quot;&quot;
      This is a test e-mail message.
      &quot;&quot;&quot;
  
      smtpObj = smtplib.SMTP('xyz@gmail.com',25)
  
      smtpObj.login('abc', 'pwd')       
      smtpObj.sendmail(sender, receivers, message)         
      print &quot;Successfully sent email&quot;
  
  
  if __name__ == '__main__':
      main()
  </code></pre>
  <p>Now when I execute the below code, I keep getting this exception:</p>
  <pre><code>smtplib.SMTPAuthenticationError: (535, '5.7.3 Authentication unsuccessful').
  </code></pre>