We recently had an issue with a slow DNS lookup (10 seconds) on our Ruby on Rails web server which caused the code to timeout and fail after about 10 seconds. This error message could be made clearer I think for future users facing similar issues?
"Oops, we failed to validate your reCAPTCHA response. Please try again."
https://github.com/ambethia/recaptcha/blob/master/test/verify_test.rb