Hi All,

I was trying to using postman with trailhead playground and referred multiple resources. It was failing initially to get the token and later it failed with error "Session expired..".

I finally reverted to use of workbench and from there a bit of discovery helped me to resolve the error. Here are my findings, hope it will be of use, if not already shared here:

• To do request token, following parameters were selected:
  • Callback URl -- https://<your org in playground>-dev-ed.lightning.force.com/oauth2/callback
    • basically picked the base url as is which was on the playground URL
  • Auth URL - https://<baseurl from above>/services/oauth2/authorization
  • ClientID - picked from connected app
  • Grant type -- Implicit
• This should give the request token successfully after prompting you for the username and password
• Once this is done, user need to select the token from drop down, click on preview headers, which should add the new access token to the headers. Verify the same.
• In URL for request don't use the same URL as above, it will not work, instead use :
  • https://<your org in playground>-dev-ed.my.salesforce.com/<path of your service>
  • this URL can be seen from Workbench -> Info --> Session Information --> Endpoint: