Following the Netlify documentation on how to setup a form, but you don't recieve submissions, this is the solution to this issue.
With my Gridsome setup, I needed to add a hidden input field:
<input type="hidden" name="form-name" value="your-form-name" />This made it work for me. Obviously replace your-form-name with the actual name of your form. exemple
<form name="Contact Form" method="POST" data-netlify="true">
<input type="hidden" name="form-name" value="Contact Form" />
<div>
<label>Your Email:</label>
<input type="email" name="email" />
</div>
<div>
<label>Message:</label>
<textarea name="message" />
</div>
<button type="submit">Send</button>
</form>