Oops something went wrong

I’ve got Mailchimp installed on WP and getting this error when trying to submit a subscription.

Oops. Something went wrong. Please try again later.

I’ve tried this link and double checked all the fields but stll getting the error:
https://mc4wp.com/kb/what-to-do-if-you-run-into-trouble/

My form contains:

<p>
    <label>Email Address</label>
    <input type="email" name="EMAIL" required="">
</p>
<p>
<p>
    <label>First Name</label>
    <input type="text" name="FNAME" required="">
</p>
<p>
    <label>Last Name</label>
    <input type="text" name="LNAME" required="">
</p>

<p>
	<input type="submit" value="Sign up" />
</p>

MC settings:

Any ideas?