Failed to send your message. Please try later or contact the administrator by an

I have activated the Recaptcha, input the site key and private key.

I am getting this message:
Failed to send your message. Please try later or contact the administrator by another method.

I can’t find the area to place this
Paste this snippet before the closing </head> tag on your HTML template:
<script src=’https://www.google.com/recaptcha/api.js’></script&gt;

Please advise

Thanks
Chris