string url = $"https://login.microsoftonline.com/{myTenantId}/oauth2/v2.0/token";
var formData = new NameValueCollection();
formData.Add("client_id", clientId);
formData.Add("client_secret", clientSecret);
formData.Add("username", username);
formData.Add("password", password);
formData.Add("scope", $"https://{myAzure}.sharepoint.com/.default");
formData.Add("grant_type", "password");
string encodedFormData = string.Join("&", Array.ConvertAll(formData.AllKeys, key =>
string.Format("{0}={1}", Uri.EscapeDataString(key), Uri.EscapeDataString(formData[key]))));
var request = (HttpWebRequest)WebRequest.Create(url);
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
byte[] formDataBytes = Encoding.UTF8.GetBytes(encodedFormData);
request.ContentLength = formDataBytes.Length;
using (var requestStream = request.GetRequestStream())
{
    requestStream.Write(formDataBytes, 0, formDataBytes.Length);
}
using (var response = (HttpWebResponse)request.GetResponse())
{
    using (var responseStream = response.GetResponseStream())
    {
        if (responseStream != null)
        {
            using (var reader = new System.IO.StreamReader(responseStream))
            {
                string responseContent = reader.ReadToEnd();
                JObject jsonResponse = JObject.Parse(responseContent);
                string accessToken = (string)jsonResponse["access_token"];
                using (HttpClient client = new HttpClient())
                {                                
                    client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
                    HttpResponseMessage response2 = await client.GetAsync($"https://{myAzure}.sharepoint.com/sites/{myPWASite}/_api/ProjectData/Ressources");
                 
                    if (response2.IsSuccessStatusCode)
                    {
                        string responseBody = await response2.Content.ReadAsStringAsync();
                        Console.WriteLine(responseBody);
                    }
                    else
                    {
                        Console.WriteLine("Erreur: " + response.StatusCode);
                    }
                }
            }
        }
    }
}