Google captcha v3 not working?

Question

reCAPTCHA

I connected the script from Google with the site key

<script src="https://www.google.com/recaptcha/api.js?render=ключ_сайта"></script>

inserted the same key into the form

<form class="ajax">
    <input type="text" placeholder="Имя" name="name">
    <input type="text" placeholder="Телефон" name="tel">
    <textarea name="txt"></textarea>
    <div class="g-recaptcha" data-sitekey="ключ_сайта"></div>
    <div id="recaptchaError"></div>
    <button class="send" data-sitekey="ключ_сайта" data-callback='onSubmit' data-action='submit'>отправить</button>
    <div class="msg"></div>
</form>

Writes the wrong key, although it is correct, what's wrong?