CAPTCHA is broken or really hard

Question

It is not possible to prove being a human!!!

There is no text to read.

Checked adblocker, nothing blocked.

Update:

To repro:

1. Open question
2. Enter 'abc'
3. Click 'Post answer'
4. Get the expected error that message is too short
5. Click 'Post answer' again
6. Presented with 'empty' CAPTCHA

Here is the HTML I receive:

<script type="text/javascript" src="http://api.recaptcha.net/challenge?k=6Ld...">
</script>

<noscript>
  <iframe src="http://api.recaptcha.net/noscript?k=6Ldchg..." ...>
  </iframe><br>
  </br>
  <textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
  <input name="recaptcha_response_field" value="manual_challenge" type="hidden"/>
</noscript>

Also I cannot even open the CAPTCHA url directly. Just end up with a Google 404 error.

I find it surprising no-one else is getting this.

Another update:

Here is what Firebug gives me:

HTTP/1.1 302 Moved Temporarily
Via: 1.1 ZAISA01
Connection: Keep-Alive
Proxy-Connection: Keep-Alive
Content-Length: 154
Date: Fri, 23 Jul 2010 11:11:49 GMT
Location: http://www.google.com/recaptcha/api/challenge?k=6LdchgIAAAAAAJwGpIzRQSOFaO0pU6s44Xt8aTwc
Content-Type: text/html
Server: nginx
P3P: CP="NOI ADM DEV PSA PSD UNI COM NAV OUR STP"

Then it 404's on the Google url.

I will try it out from home tonite, seeing this is a work connection.

Update:

It works from home. I get a JSON reponse from the URL I provided earlier. I can only assume this is some proxy issue, as it used to work.

Final update:

We got a new proxy installation at work, and it started working magically even though all the rules were replicated...

At least it works now :)

Answer 1

Some general pointers to debug this:

1. Check the JavaScript console for errors.
2. Is scripting allowed?
3. Try again after a few minutes; maybe there was a problem with the captcha provider
4. Are you behind a proxy?
5. I guess the captcha is embedded using an iframe or something like that. Check the source code of the page for any oddities.

Answer 2

We can't reproduce this in any browser.