Hi,

I'm encountering an issue with the Strava API when trying to retrieve activities. Despite following the OAuth flow as per the Getting Started documentation, I consistently receive the following error:

{
    "message": "Authorization Error",
    "errors":  
        {
            "resource": "Athlete",
            "field": "access_token",
            "code": "invalid"
        }
    ]
}

Here’s what I’ve done so far:

1. Generated an authorization code using the following URL:

   https://www.strava.com/oauth/authorize?client_id=143540&redirect_uri=http://localhost&response_type=code&scope=activity:read_all
   

2. Exchanged the authorization code for an access token and refresh token:

   https://www.strava.com/oauth/token?client_id=143540&client_secret=****&code=****&grant_type=authorization_code
   

3. Used the access token to fetch activities:

   https://www.strava.com/api/v3/athlete/activities?access_token=****
   

However, the access token always returns the "invalid" error. I verified the following:

• The redirect_uri matches what’s in my Strava app settings (http://localhost).
• The requested scope includes activity:read_all.
• I even tested using the Strava API Playground, but it fails with a "Bad Request" error:

  {
      "message": "Bad Request",
      "errors": r
          {
              "resource": "Application",
              "field": "redirect_uri",
              "code": "invalid"
          }
      ]
  }
  

I suspect there might be an issue with my app configuration or how the tokens are being generated/used. Can someone help identify what might be going wrong?

Thanks in advance for your support!