Question:

Few months back I prepared a demo on Fitbit oauth2 public APIs in which I used to log in with a particular user and get his activities. It was working fine. But recently, I opened the demo and tried to log in with the same user but it is not getting logged in and repeatedly giving me this error.

<a href="https://i.stack.imgur.com/Q0jaC.png" rel="nofollow"><img alt="enter image description here" class="b-lazy" data-src="https://i.stack.imgur.com/Q0jaC.png" data-original="https://i.stack.imgur.com/Q0jaC.png" src="https://etrip.eimg.top/images/2019/05/07/timg.gif" /></a>

I tried to change the client secret key of this demo app which I registered on Fitbit but nothing happened. I am stuck here.

There is problem with the format of <strong>Callback URL</strong>. I think Fitbit has recently changed it.

Earlier, the format of Callback URL was "demoapp://" but now it will be "demoapp://something"

Please refer to my answer on other question.

<a href="https://stackoverflow.com/questions/37318219/setting-up-fitbit-api-in-xcode-swift/52380947#52380947" rel="nofollow">Setting up Fitbit api in xcode Swift</a>