Google reCaptcha - An internal error occurred
Recaptcha is a free CAPTCH service offered by google in the fight against automatic html form submission as it is exploited for spam purposes.
According to Google documents https://code.google.com/p/recaptcha/wiki/HowToSetUpRecaptcha
The keys are unique to your domain and sub-domains and will not work for other domains unless you:
Sign up for multiple keys (one for each site)
Create a global key by checking the box for "Enable this key on all domains (global key)"
An internal error occurred: XXXXXXXXXXXXXXXXXXXX
This is an reCaptcha internal error that occurs when the domain hosting recaptcha scripts changes without the new domain being enabled in the reCaptcha key. Your browser sends a request to google server using a public key and referer from your new domain (where it doesn't work) which hasn't been enabled for the reCaptcha key. That public key is linked to your old domain, thus your browser will execute the recaptcha script and in return it will get a reject from the server.
Fix reCaptcha "An internal error occurred"Go to https://www.google.com/recaptcha/admin and submit the new domain to the key.