Is delegation deprecated in Auth0?

Question

I'm trying to POST to a Auth0 delegation URL to obtain an access token and getting a "Grant Type not allowed" error as seen below. (This is when not using Postman.)

I came across a post in the forums that Delegation is deprecate in Auth0. Can anyone confirm if that is the issue here and if I'm trying something that's not available anymore?

Request:

Content-Type: 'application/json'

{
  "client_id":   "ID",
  "grant_type":  "urn:ietf:params:oauth:grant-type:jwt-bearer",
  "id_token":    "TOKEN",
  "target":      "lwTL1rYVfC0KsBUFPeKWY3HvGjbIgdDM",
  "api_type":    "salesforce_api",
  "scope":       "openid"
}

Error:

{
"error": "unauthorized_client",
"error_description": "Grant type 'http://auth0.com/oauth/legacy/grant-type/delegation/id_token' not allowed for the client.",
"statusCode": 403,
"error_uri": "https://auth0.com/docs/clients/client-grant-types"
}

Related Question:

"Missing grant-type parameter" in Auth0 Delegation endpoint call

In that question, using Postman to call the endpoint with the same request results in a different error!