title: How can I fix `DiscordAPIError: Cannot send messages to this user`?
body: <p>I'm making a new command that sends the author a message, however, when the author's DMs is closed it's giving me the error <code>DiscordAPIError: Cannot send messages to this user</code></p>
  
  <pre><code>    if (!message.author.send) {
          return message.channel.send("DMs closed.");
      } else {
          message.author.send("DMs opened")
      }
  </code></pre>