Captcha not valid

Hello, i recently upgraded from php7.3 to php7.4, all my forms stopped working. With some help from users on discord i had to change the way recaptcha was coded in the form. Now the form displays but captcha returns with an error. Captcha not valid.

In the grav.log i found an error message:

Form reCAPTCHA Errors: [/contact] ["missing-input-response"]

What causes this problem?

Here is the complete

title: Contact

    name: contact

        - name: name
          label: Naam
          placeholder: Uw naam
          autocomplete: on
          autofocus: true
          type: text
            required: true

        - name: email
          label: Emailadres
          placeholder: Uw emailadres
          type: email
            required: true

        - name: message
          label: Bericht
          placeholder: Uw bericht
          type: textarea
          rows: 5
            required: true

        - name: honeypot
          type: honeypot

          label: Captcha
          type: captcha
          recaptcha_not_validated: 'Captcha not valid!'

        - type: submit
          value: Verzenden
        - type: reset
          value: Wis formulier

        - captcha: true
        - email:
            to: "{{ }}"
            subject: "Contactformulier"
        - message: Bedankt voor uw bericht!
        - display: /thankyou

## Contact formulier

Via onderstaand formulier kunt u contact met ons opnemen.