Did you fill in the 3 feilds on MailChimp?
<form action="https://<strong>testing</strong>.us4.list-manage.com/subscribe/post?u=<strong>f21fc7561adfab29fc8117e59</strong>&id=<strong>6603ef9133</strong>" method="post" id="mc-embedded-subscribe-form" name="mc-embedded-subscribe-form" class="validate" target="_blank" novalidate>
<label for="mce-EMAIL">Subscribe to our mailing list</label>
<input type="email" value="" name="EMAIL" class="email" id="mce-EMAIL" placeholder="email address" required>
<div class="clear"><input type="submit" value="Subscribe" name="subscribe" id="mc-embedded-subscribe" class="button"></div>
</form>
U => f21fc7561adfab29fc8117e59
Id => 6603ef9133
Action => testing
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