Error in Sentiment Analysis - Azure

Hello world.

I am using Azure Cognitive Services API to analysis each customer answers in our NPS forms, and return Key Phrases, according to this tutorial and it is working fine.

I also want a Sentiment Analysis score, and so I created another custom function to measure this, like the tutorial says:

(text) => let
    apikey      = "<MY_KEY>",
    endpoint    = "https://<MY_DENTPOINT_DOMAIN>.cognitiveservices.azure.com/" & "/text/analytics/v3.0/sentiment",
    jsontext    = Text.FromBinary(Json.FromValue(Text.Start(Text.Trim(text), 5000))),
    jsonbody    = "{ documents: [ { language: ""pt-br"", id: ""0"", text: " & jsontext & " } ] }",
    bytesbody   = Text.ToBinary(jsonbody),
    headers     = [#"Ocp-Apim-Subscription-Key" = apikey],
    bytesresp   = Web.Contents(endpoint, [Headers=headers, Content=bytesbody]),
    jsonresp    = Json.Document(bytesresp),
    sentiment   = jsonresp[documents]{0}[detectedLanguage][confidenceScore]
    in  sentiment

And all I got is errors like this:

Erro na consulta ‘’. Expression.Error: O campo 'detectedLanguage' do registro não foi encontrado.
Detalhes:
    id=0
    sentiment=positive
    confidenceScores=
        positive=0,99
        neutral=0,01
        negative=0
    sentences=[List]
    warnings=[List]

What could I do?