Device Authorization: "unsupported grant type" requesting access token

Meeting SDK Type and Version
My app is a Meeting SDK App

First get a device_code like this:

curl -X POST
-d ‘client_id=’
-d ‘client_secret=’

Visit the verification URI to add the app.

Now use the device code to request an access token.
Here is the attempted POST:

*curl -X POST *
*-H ‘Content-Type: application/x-www-form-urlencoded’ *
*-H ‘Host:’ *
*-H ‘Authorization: Basic ’ *
-d ‘device_code=&grant_type=urn:ietf:params:oauth:grant-type:device_code’

Here is the error response:

  • “reason”: “unsupported grant type”,*
  • “error”: “unsupported_grant_type”*

Troubleshooting Routes
I am able to use my server-to-server OAuth flow to create access tokens, but I need to figure out device authorization for this app.
App is Live, but not published (no intention to publish)

How To Reproduce
See steps above.
Using Chrome on Windows 10