Running code sample shown on Azure AI Translate website, but the response is not the same. It detects the wrong language

I tried running the example found on the Azure website on the following URL:

https://learn.microsoft.com/en-us/azure/ai-services/translator/text-translation/how-to/use-rest-api?tabs=nodejs#detect-source-language-during-translation 

The example is under the "Detect source language during translation" section. However, the request does not get the expected response.

Here is my code:

let params = new URLSearchParams();
params.append("api-version", "3.0");
params.append("category", "general");
params.append("to", "en");
params.append("to", "it");

axios({
    baseURL: "https://api.cognitive.microsofttranslator.com",
    url: '/translate',
    method: 'post',
    headers: {
        'Ocp-Apim-Subscription-Key': key,
        // location required if you're using a multi-service or regional (not global) resource.
        //'Ocp-Apim-Subscription-Region': location,
        'Content-type': 'application/json',
        'X-ClientTraceId': uuidv4().toString()
    },
    params: params,
    data: [{
        'text': 'Halo, rafiki! Ulifanya nini leo?'
    }],
    responseType: 'json'
}).then(function (response) {
    console.log(JSON.stringify(response.data, null, 4));
})

Here is the response I get:

[
    {
        "detectedLanguage": {
            "language": "en",
            "score": 1
        },
        "translations": [
            {
                "text": "Halo, rafiki! Ulifanya nini leo?",
                "to": "en"
            },
            {
                "text": "Aureola, rafiki! Ulifanya nini leo?",
                "to": "it"
            }
        ]
    }
]

I tried changing setting the value for "category" parameter to "general" or "generalnn" but still getting the same response as above. Please note that the code I run is the same as the one shown in the example in the give URL above.

My question is what are we doing wrong? Could anyone advise us?