title: TypeError [ERR_INVALID_CALLBACK]: Callback must be a function. Received undefined
body: <p>I have a little problem with my captcha code.</p>
  <pre class="lang-js prettyprint-override"><code>client.on('guildMemberAdd', async member =&gt; {
      const captcha = await createCaptcha();
      try {
          const msg = await member.send('Vous avez 60 secondes pour resoudre ce captcha !', {
              files: [{
                  attachment: `${__dirname}/captchas/${captcha}.png`,
                  name: `${captcha}.png`
              }]
          });
          try {
              const filter = m =&gt; {
                  if (m.author.bot) return;
                  if (m.author.id === member.id &amp;&amp; m.content === captcha) return true;
                  else {
                      m.channel.send('Vous avez mal rentrer le captcha.');
                      return false;
                  }
              };
              const response = await msg.channel.awaitMessages(filter, {
                  max: 1,
                  time: 20000,
                  errors: ['time']
              });
              if (response) {
                  await msg.channel.send(&quot;Vous venez de vous vérifier ! Vous avez alors l'accès complet au serveur&quot;);
                  await member.roles.add('737228969426026635');
                  await fs.unlink(`${__dirname}/captchas/${captcha}.png`)
                      .catch(err =&gt; console.log(err));
              }
          } catch (err) {
              console.log(err);
              await msg.channel.send(&quot;Vous n'avez pas résolu le captcha.&quot;);
              await member.kick();
              await fs.unlink(`${__dirname}/captchas/${captcha}.png`)
                  .catch(err =&gt; console.log(err));
          }
      } catch (err) {
          console.log(err);
      }
  });
  </code></pre>
  <p>And I have this error:</p>
  <pre><code>TypeError [ERR_INVALID_CALLBACK]: Callback must be a function. Received undefined
      at makeCallback (fs.js:152:11)
      at Object.unlink (fs.js:1118:14)
      at Client.&lt;anonymous&gt; (C:\Users\wstep\OneDrive\Bureau\DaliaMC\index.js:88:22)
      at processTicksAndRejections (internal/process/task_queues.js:97:5) {
    code: 'ERR_INVALID_CALLBACK'
  }
  </code></pre>
  <p>There is a capture from what the bot says</p>
  <p>What the bot says =&gt; <img src="https://i.stack.imgur.com/D0II5.png" alt="bot_reply" /></p>
  <p>Thank you for your help!</p>