Unauthorized error when trying to get access token

[Leonard_]

Developer information: unauthorized_client - A "Personal" application is only authorized to request access tokens from the owner of the application.

I have successful get the redirect link something like

https://example.com/#access_token=<token>&user_id=XXXXXX&scope=activity+profile&token_type=Bearer&ex...

But when I trying to login with another email, it give me error. 

I can access myself account JSON.

I am using 

Implicit Grant Flow

1. How do get access to other user JSON?

Example JSON I request for

"https://api.fitbit.com/1/user/-/activities/steps/date/today/1m.json"

"...../-/ " <- this is for current user, should I change something with that? But how do I authorized that.

Well, I am using Unity C# and plan to built in Android, hope experiance people can help me further......

[JeremiahFitbit · Accepted solution]

A "personal app" can only retrieve the data of the person who registered the app.

If you want to build an app to access other people's data, you have to pick client or server app. If you want intraday data for other people, you'll need to request access for your use case as documented here.