Hi, I am having the same issue. The checkbox is not shown on the contact us page and the form cant be send because of human veirfication error.

I checked all four of your checklist and all looks fine.
The only idea i have is about the keys. When i enroll reCaptcha settings to create a key, google gives 1 key only and it seems to be the site key. So i really have no idea, after googling it for long, where to get or create the secret key.

Any ideas please?

thanks,