Solved
ReCAPTCH V3 Error for site owner message
Hello,
I watched @SanfordWhiteman 's webinar on implementing Google reCAPTCHA V3 in Marketo. The steps are very clear and I thought I was doing everything right, but I'm getting an error on the first step!

I identified these domains:

And got my site key:

Which I added to the script to test in codepen.io.
I'm hoping that I'm missing something obvious here.
Thanks,
Tadia