title: How to access user Google Fit data from backend
body: <p>I write backend ASP .NET Core API and I need to read user Google Fit data. </p>
  
  <p>I created an Android app that gets the server auth code and sends it to backend. As far as I understand, I need to get user token and then use it to access Google Fit. I tried to find libraries for it and failed. I also tried to get user token using Postman and got the following error:</p>
  
  <pre><code>{
      "error": "invalid_grant",
      "error_description": "Bad Request"
  }
  </code></pre>
  
  <p>Am I doing something wrong?</p>