I cannot see any captcha, therefore the form does not work: https://www.mozilla.org/en-US/legal/fraud-report/index.html

Hmmm, could it be... The script that creates the CAPTCHA is on an insecure (HTTP) URL. Firefox 23 implements a new feature of blocking certain insecure content on secure pages ("mixed content blocking"). Two ways to check for that: * On the left side of the address bar where you normally see a lock or globe, is there a shield icon? If so, click that and (based on what I have read) you should be able to approve the insecure content. * Or if you manually edit the address bar from HTTPS to HTTP and load it that way, can you see the ReCaptcha box? If this is the problem, then someone needs to fix that page ASAP!