Help with Tesla Powerwall API V3

[gjniewenhuijse]

problem found, grant_type incorrect transfered

Code:

function GetToken()
  body = json.encode({
    grant_type = 'refresh_token',
    client_id = 'ownerapi',
    refresh_token = refreshToken,
    scope = 'openid email offline_access'     
  })

  resp = {}

  res, code, headers = http.request({
    url = 'https://auth.tesla.com/oauth2/v3/token',
    method = 'POST',
    source = ltn12.source.string(body),
    sink = ltn12.sink.table(resp),
    headers = {
      ['Content-Type'] = 'application/json',
      ['Accept'] = 'application/json',
      ['Content-Length'] = #body   
      }
  })
  if not res or code ~= 200 then
    return
  end
  resp = table.concat(resp)
  resp = json.pdecode(resp)
 
  bearer_token = resp.access_token
  --refresh_token = resp.refresh_token
 
    return bearer_token
end

And next? do i need to refresh some tokens?