invalid_request - Invalid redirect_uri parameter value

[x509]

I have searched through all possible answers here but i am unable to solve this issue. I have registered my app like this

Application Website: http://localhost:8080

Organization Website: http://localhost:8080

Callback URL: http://localhost:8080/fitbitauth.xml

And then I have following url which i am using to authorize

http://www.fitbit.com/oauth2/authorize?response_type=token&client_id=XXXXX&redirectUri=http%3A%2F%2Flocalhost%3A8080%2Ffitbitauth.xhtml&scope=activity%20heartrate%20location%20nutrition%20profile%20settings%20sleep%20social%20weight&expires_in=604800

 But even then I get the same response i.e., invalid redirect_uri ... 

Before you you guys say anything that its on localhost, I have tried putting my app on Heroku and still same issue (ofcourse i changed my urls in my app)

On heorku i was generating the callback url like 

HttpServletRequest request = (HttpServletRequest) FacesContext.getCurrentInstance().getExternalContext().getRequest();
String resultPage = request.getRequestURL().toString() + "fitbitauth.xhtml";

Which resulted in http://<app_name>.herokuapp.com/fitbitauth.xhtml

Could someone please help me solve this issue.  

[AndrewFitbit]

@x509 The redirect_uri needs to match the callback url in your app settings, that's why you're seeing invalid redirect_uri error.

In your callback url you have ".xml" at the end but looks like your redirect_uri has ".xhtml".