domain redirection has been confirmed

[renobody]

Dear Sir or Madam

This is Mr.Murakami of Neos Corp.

Our "Renobody" iOS app allows limited domain access only and allows "Fitbit.com" when using your API.
However, the following domain redirection has been confirmed from the most recent authentication screen.
(hen, we couldn't access to the authentication screen.)
cloudfront
fls.doubleclick.net

We would like to ask for one or more of the following to resolve the issue.
1. Stop redirection from the authentication screen
OR
2. Disclose domains that may redirect from the authentication screen

Sincerely

[IoanbsuFitbit]

renobody,

To better understand where redirection is happening, could you please post here the url for the [authentication screen] that you talk about in your post. Feel free to replace any security related data in it. 

Could you also please PM to me you app id?

If you can post steps to reproduce here it would be delightful, as we can try following these steps to reproduce it on our end and be able to debug the issue.

[renobody]

Service
　Renobody　 App ID：2294P2

Current Status
  When we access below URL from Renobody App to authenticate
    https://www.fitbit.com/oauth2/authorize

  Then a domain other than the Fitbit service is detected at that time, 
  it becomes a browser start to display that page
  * in Renobody, domains other than "Fitbit.com" and "Api.fitbit.com" do not allow access.

  Detected URL are below
    https://4272175.fls.doubleclick.net/activity
    https://20766817p.rfihub.com/ca.html
    https://staticxx.facebook.com/connect/xd_arbiter/r/_dMxoUH0Bax.js

How to Replay
  1. iOS Renobody app DL from Apple store
  2. Register (required User name, e-mail address, and PW)
  3. Setting
  4. Select fitbit device and setting
  5. Then, launch Safari and direct to below URL
       https://4272175.fls.doubleclick.net

[renobody]

Thank you for your reply We will inform you of URL details.

https : //www.fitbit.com/oauth2/authorize?scope=activity%20heartrate%20location%20nutrition%20profile%20settin...