title: Postfix - Must issue a STARTTLS command first - revisited
body: <p>I'm running MacOS Sierra, and this is the first time I've seen '/etc/ssl/certs' in my system. It doesn't exist in Yosemite or earlier. But that directory is EMPTY, so I have no clue what to supply for the certificate to use Gmail. Until I get that, I can't supply 'smtp_tls_CAfile' in main.cf so 'smtpd_use_tls=yes' works.  All my sent mail is being rejected by this:</p>
  
  <pre><code>530 5.7.0 Must issue a STARTTLS command first 
  </code></pre>