The Captcha page on this site doesn't seem to be set up correctly, it shows an error message:
ERROR for site owner:
Invalid domain for site key
The Captcha page on this site doesn't seem to be set up correctly, it shows an error message:
ERROR for site owner:
Invalid domain for site key
Captcha wasn't configured correctly for Stack Apps on our end. The issue has been fixed.
Sorry for the inconvenience, and thanks for the report!