Using the ReCaptcha on your website during development, using localhost to view your pages, may give you the Localhost is not in the list of supported domains for this site key.
Issue Details
The reCAPTCHA no longer supports the use of localhost by default. If you run your page with the Localhost in the URL. You will receive the following error.
ReCaptcha Error Localhost is not in the list of supported domains for this site key.
Recreate Issue
http://localhost/Site/Page.asp
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when using the newest version of the ReCaptcha plugin.
Resolve Issue
Instead of using localhost to access your pages on your development machine. Use the 127.0.0.1