Add this to your index.html

index.html

<!--dummy form so netlify knows what's coming-->
    <form name="contact-speaker" netlify netlify-honeypot="bot-field" hidden>
      <input type="text" name="name" />
      <input type="text" name="email" />
      <textarea name="message"></textarea>
      <input type="text" name="speaker" />
    </form>