404 - "PowerBIEntityNotFound" - issues getting embed token

Hi there, I'm trying to get te embed token to make some proves on playground.

once i have my prooves on rails the back end will connect with appi and passme accessToken to consume de pbio APIREST from my react app(wich i couldn't connect withouth a anoying popup). we are using app owns data approach.

My route:

1: get mi groups bi RESTAPI: get groups

2: get mi reports so i can get report id: get dashboards in group 

3: additional get mi daataset id in case that i'll need it: get dataset in group

throught here, everithing is okay.

4: get my embed token to playground my dashboards, and make react proves: reports generate token in groups

my body query:

{
  "accessLevel": "View",
  "identities": [
    {
      "username": "User",(i'd tryied everything)
      "roles": [
        "sales"(tryied everything: Owner, Administrator, cliente:pbi desktop report config)
      ],
      "datasets": [
        "my_data_set_id"
      ]
    }
  ]
}

through this process i get an 404 error "PowerBIEntityNotFound". i can not figure out where can i get my user an role that i need, or why i need it i have not data level acces to config. The error:

{
  "error": {
    "code": "PowerBIEntityNotFound",
    "pbi.error": {
      "code": "PowerBIEntityNotFound",
      "parameters": {},
      "details": [],
      "exceptionCulprit": 1
    }
  }
}

my path:

get pbi pro lisence and an azure app to apps own data approach

get pbi service on azure to add capacities to my worspaces on app.powerbi.com(creat a user to admin it)

set capacities on my workspaces, now seeing an diamond on it.

have azure paid services