Error when recaptcha enabled

Where can we see the website in question?

Hi @takayukister

the site here

But I’ve disabled recaptcha to avoid the error.

What other plugins and theme do you use on the site?

Akismet Anti-Spam
Beehive Analytics
Classic Editor
Contact Form CFDB7
Defender
Groovy Menu (free)
SiteOrigin Page Builder
Shortcodes Ultimate
SiteOrigin Widgets Bundle
WP Fastest Cache
Yoast SEO

Try switching to the default theme, deactivating all plugins excluding Contact Form 7, Akismet Anti-Spam, Classic Editor and Yoast SEO, and clearing all cache data.

Why you are advised to deactivate plugins and switch to the default theme.

@takayukister It’s a bug with my child theme, already fixed it. Thanks.