var values = new Dictionary<string, string>
        {
            { "client_id", ClientId },
            { "scope", "openid offline_access https://graph.microsoft.com/.default" },
            { "client_secret", clientSecret },
            { "grant_type", "client_credentials" }
        };

        var content = new FormUrlEncodedContent(values);

        var response = await client.PostAsync($"https://login.microsoftonline.com/{**tenantID**}/oauth2/v2.0/token", content);

        string token = await response.Content.ReadAsStringAsync();

        JObject accessToken = JObject.Parse(token);
        string access = (string)accessToken["access_token"];
        return access;

var url = $"https://login.microsoftonline.com/{tenantDomain}/adminconsent?"
                  + $"client_id={ClientId}"
                  + "&state=12345"
                  + "&redirect_uri=http://localhost";

var verifyButtonClick = function () {
 var url = $"https://login.microsoftonline.com/{tenantDomain}/adminconsent?"
        + "client_id=" + $("#clientID").val()
        + "&state=12345"
        + "&redirect_uri="+ window.location.href.split("?")[0];
    window.open(url);
}

HttpClient client = new HttpClient();
        client.BaseAddress = new Uri(url);
        client.DefaultRequestHeaders.Accept.Add(new
        MediaTypeWithQualityHeaderValue("application/json"));
        HttpResponseMessage response = client.GetAsync(url).Result;