Rimas

Hi, I've faced this problem today as well, when trying to register. @tcit's solution (modifying the bits related to headers in captcha.js) helped me. I believe I know why not everyone faces the issue: as mentioned in @tcit's response, this problem only surfaces when an attempt to place non-ascii characters in the HTTP headers are made, and this doesn't happen to everyone. In my case, it happened because my browser locale, as well as my OS locale, are Lithuanian, so the following code: new Date(0).toString() (note: `toString()` was added by me here) produces the following response in the browser console: Note how the name of the time zone is in Lithuanian and contains a couple accented letters. Meanwhile, the code, as suggested by @tcit, looks like this: new Date(0).toISOString() and produces the following output: I finally managed to register after adding a breakpoint in line 20 of `captcha.js` and running a modified `$.ajaxSetup()` call in browser console. BTW, the problem happens in both Firefox and Chromium. I'm so surprised this has stayed unfixed for years...