How can I verify my domain with Google to resolve the 'Invalid Domain for Site Key' error?

To verify your domain with Google, you need to add a TXT record to your domain's DNS settings. Go to the Google Search Console and add a new property, specifying your website's domain. Google will provide a unique TXT record value. Add this TXT record to your domain registrar's DNS management panel. DNS propagation can take up to 48 hours, so be patient. Once propagated, re-verify in Google Search Console.