Unauthorized access

I am getting this when trying get all stages.
{“success”:false,“error”:“unauthorized access”,“errorCode”:401,“error_info”:"Please check developers.pipedrive.com}

Can you describe the error and use case in detail?
We also have a sample app that has the OAuth flow already setup GitHub - pipedrive/FiftyFifty: Example app for Pipedrive Marketplace

Feel free to create a new topic if you are still facing the challenge