Parsing Json from www response


I have webService that return to my Unity apllication a Json response. I use the www class. When I retreive he response with the response.text and I try to parse it with my JsonParser ( I use the Json.Net), it make me this error : " JsonReaderException: Unexpected character encountered while parsing value: . Path ‘’, line 0, position 0"

When I replace the response by a static String the same that my server reply with it works fine.!!!
I log the response.text from Unity to a Json Validator, it told me that isn’t valide. My response began with a hiden a hidden caracter that I supposed that response of the www class add to my server reply!!!
I use the Unity 4.6 is that a Bug for this version or what!? Please help!!

Hi, I could resolve my problem with this solution posted in this url : WWW.text string not correct? - Unity Answers

there must be other text after your json string like

{"user_ id":0, "token":"sdddas"} <html>bla bla bla</html>

.Json parser is trying to parse that too which is causing issue.