title: BBC emails not being sent with MailComposer and Nodemailer
body: <p>I am using Google cloud functions to send emails using Nodemailer. I am using the MailComposer module to send emails with formatting (line breaks and HTML etc).</p>
  
  <p>Here is my code:</p>
  
  <pre><code>const mailOptions = {
        from: `${name} joanne@bloggs.com`,
        replyTo: `${name} ${email}`,
        to: user.email,
        bcc: 'jo@bloggs.com',
        subject: `Direct message from ${name}`,
        text: `${message}`
      }
  
      let mail = new MailComposer(mailOptions).compile()
  
      mail.keepBcc = true
  
      console.log('mail', mail)
  
      return mail.build((error, message) =&gt; {
        if (error) {
          console.log('Email unsuccessful', error)
          res.status(400).send(error)
        }
        const dataToSend = {
          to: user.email,
          bcc: 'jo@bloggs.com',
          message: message.toString('ascii')
        }
        return mailgun.messages().sendMime(dataToSend, sendError =&gt; {
          if (sendError) {
            console.log('Email unsuccessful', error)
            res.status(400).send(error)
          }
          return res.send('Email successfully sent!')
        })
      })
  
  </code></pre>
  
  <p>The problem I am having is that emails are not sent to the BBC recipient, but are sent to the TO recipient. I have tried following the documentation and adding the keepBcc option with no success. Does anyone know what I am missing?</p>