NodeJS NTML syntax for a POST ressouce

Question

I'm trying to call a webex ressource from my application, but always get the following error : getaddrinfo ENOTFOUND webexapis.com

The thing is, I got a tip I needed to implement a NTLM authentification to comply to the company's proxy policy, but all samples I could find so far concern GET calls.

I have two versions of my code. The first one, voluntarily light, just to check if my syntax is correct. I hope for a "invalid credentials" or a "missing credentials" kind of error, which would tell me I'm on the right tracks :

const credentials: NtlmCredentials = {
    username: 'my-app-id',
    password: 'my-app-secret',
    domaine: 'my-company-domain'
}
const client = NtmlClient(credential);
try {
    const response = await client({
        url: 'https://webexapis.com/v1/access_token',
        method: 'POST'
    });
    console.log('success: ', response);
} catch(err) {
    console.log('error:', err);
}

This is the bloc of code that gives me the getaddrinfo ENOTFOUND error.

I also have a second bloc, more complete, more like what I would need in finite, but that still yields the same error:

const data = qs.stringify({
    grant_type: 'authorization_code',
    client_id: 'my-client-id',
    client_secret: 'my-client_secret',
    code: 'auth-code',
    redirect_uri: 'my-redirect-uri'
});
const config: AxiosRequestConfig = {
    method: 'post',
    url: 'https://webexapis.com/v1/access_token',
    headers: {
        'Content-Type': 'application/x-www-form-urlencoded',
    },
    data: data
};
axios(config)
    .then(res => console.log(JSON.stringify(res.data)))
    .catch(err => console.log(err));

Am I missing something obvious or does the problem only depends on my proxy/company configurations ?