Error: ReCAPTCHA placeholder element must be empty

You are loading the google recaptcha library twice.

https://www.google.com/recaptcha/api.js

You are loading the library 2 times

chose

<script src="https://www.google.com/recaptcha/api.js?onload=onloadCallback&render=explicit" async defer></script>

or

     <script src="https://www.google.com/recaptcha/api.js" async defer></script>