GatsbyJS & Netlify forms change subject

I’ve created a Netlify form on my GatsbyJS site on bolig-partner.dk. The form itself works just fine. However, I am having issues changing the subject of my form. I have followed the instructions found in the Netlify forms documentation

I am using a hidden field in order to set subject of my form:

<input type="hidden" name="subject" value="My subject" />

I am receiving submission from the form but the subject is not taking effect. What am I missing ??

The form itselves I am using:

 <form
              name="contact"
              method="POST"
              data-netlify="true"
              className="hero-form"
              data-netlify-honeypot="bot-field"
            >
              <input type="hidden" name="form-name" value="contact" />
              <input type="hidden" name="bot-field" />
              <input type="hidden" name="subject" value="My subject" />
              <p>
                <input type="text" name="name" placeholder="Dit navn" />
              </p>
              <p>
                <input type="email" name="email" placeholder="Din email" />
              </p>
              <p>
                <input type="phone" name="phone" placeholder="Dit tlf. nr." />
              </p>
              <p>
                <textarea
                  name="message"
                  placeholder="Skriv evt. hvad det handler om"
                  rows="5"
                ></textarea>
              </p>
              <p>
                <button type="submit">Send</button>
              </p>
            </form>

After doing some research I found a error in my code:

Failed form propType: You provided a value prop to a form field without an onChange handler. This will render a read-only field. If the field should be mutable use defaultValue. Otherwise, set either onChange or readOnly.

so I changed value to be defaultValue instead:

<input type="hidden" name="subject" defaultValue="My subject" />

However, this doesn’t seem to make any difference.

Hello @bolig-partner, welcome to the community!

Since the way you are using the subject field seems to be read-only, I don’t think you need to use the defaultValue prop. Leaving the value prop should be sufficient for your current purposes.

That said, could you point to your live form? What subject are you seeing when you get the form submission notification?