Your storefront includes a contact form and account for repeat customers to save their shipping information. In order to reduce the amount of spam that may be received through the contact form and increase security for customer password reset forms the storefronts leverages Google reCAPTCHA v2 to prevent automated submissions.
If your storefront or SSL was launched in 2021 or later, you will be required to sign up for your own reCAPTCHA credentials to leverage this security feature for your storefront. Sign up for your reCAPTCHA API key pair here.
Once you've acquired your reCAPTCHA credentials, you may save them in Settings > Storefront > Website.