Recently, I’m busy with the development of Fitbit. I used API Client Libraries from - https://github.com/aarondcoleman/Fitbit.NET/. But I know little about the development of Fitbit, after inputting the users’ account and password, the system was always prompts an error, and I was unable to obtain the users’ data. It displayed a message saying: "The page is no longer valid, perhaps you supplied an invalid proof of identity or someone is using the proof of identity that you provided, please return to the web site or application which sent you to the page and try again later.”
There are URLs：
https://api.fitbit.com/oauth/logout_and_authorize?oauth_token=d3f799ea0b4db756c644cb0f718f1217
https://www.fitbit.com/oauth/authorize?oauth_token=d3f799ea0b4db756c644cb0f718f1217&oauth_verifier=6...
Fitbit Developers oversee the SDK and API forums. We're here to answer questions about Fitbit developer tools, assist with projects, and make sure your voice is heard by the development team.
Best Answer
