Requesting people.json not working get a 404

I'm looking at some code someone else on our project wrote and think there is a problem. Currently a request goes out to

"http://api.getsatisfaction.com/people.json?email=bus.test@mailinator.com" however that gets a 404

if I remove the .json that request works fine with a HTML response, I looked at the docs as also suggests changing the accept header to text/x-json. However when I do this I get a 401 Unauthorised response. Could someone point me in the direction of what the request should be for a JSON response.

Any pointers will be very useful, thanks in advance.