title: Nodemailer - unable to get local issuer certificate
body: <p>I am trying to send a email using Nodemailer with these configurations : </p>
  
  <pre><code>var transporter = nodemailer.createTransport(smtpTransport({
            host: 'smtp.outlookhost',
            port: 25,
            auth: {
              user: '',
              pass: ''
            },
            secure:false,
            logger: true,
            debug: true
          }));
  </code></pre>
  
  <p>I am getting this error : </p>
  
  <pre><code>Error: unable to get local issuer certificate
  </code></pre>
  
  <p>I am using outlook to send email. How can I provide certificates.</p>
  
  <p>Modified the configurations :</p>
  
  <pre><code> var transporter = nodemailer.createTransport(smtpTransport({
                host: 'smtp.outlookhost',
                port: 25,
                auth: {
                  user: '',
                  pass: ''
                },
                secure:true,
                logger: true,
                debug: true,
                tls: {
                // do not fail on invalid certs
                rejectUnauthorized: false
              }
      }));
  </code></pre>
  
  <p>Error : </p>
  
  <pre><code>Error: 101057795:error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol:openssl\ssl\s23_clnt.c
  </code></pre>