I want to get an access token from given URL:
https://login.microsoftonline.com/{AzureTenantId}/oauth2/v2.0/authorize

I am passing the following parameters, as mentioned in he Microsoft docs: client_id, scope, client_secret, grant_type, resource and audience.

When I hit this URL, I get a “403 Forbidden” response.
When I try the same from Bruno, it succeeds:

But not from my code:

public HttpStatusCode InvokeWebAPIPostJson(string apiBaseURL, string urlSuffix, SaveCommentModel saveCommentModel)
{
    var token = WebAPIControllerExtensions.GetAuthenticationTokenAsync(this.configuration, ApplicationConstants.AUTHORITY_BASEURI, ApplicationConstants.GRANT_TYPE, ApplicationConstants.SCOPE, ApplicationConstants.CONTENT_TYPE);
    double cltTimeout = ApplicationConstants.HTTPCLIENT_TIMEOUT;
    var url = apiBaseURL ?? string.Empty;

    using var httpRequestClient = new HttpClient();
    httpRequestClient.Timeout = TimeSpan.FromMinutes(cltTimeout);
    httpRequestClient.BaseAddress = new Uri(url);
    httpRequestClient.DefaultRequestHeaders.Accept.Clear();
    httpRequestClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
    httpRequestClient.DefaultRequestHeaders.Add("Accept", "*/*");
    httpRequestClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
    string saveComment = JsonConvert.SerializeObject(saveCommentModel);
    var stringvar = """ + saveComment + """;
    StringContent jsonContent = new(saveComment, Encoding.UTF8, "application/json");

    var resp = httpRequestClient.PostAsync($"{urlSuffix}", jsonContent).Result;
    var statusCode = resp.StatusCode;
    return statusCode;
}

// getting the token by using htis below method:

        public static string GetAuthenticationTokenAsync(
            IConfiguration configuration, string authBaseURL, string grantTypeStr
            , string scopeStr, string contentType)
        {
            var audienceVal = configuration["Keyvault:Audience" + string.Empty] ?? string.Empty;
            var clientIdVal = configuration["Keyvault:ClientId" + string.Empty] ?? string.Empty;
            var secretVal = configuration["Keyvault:Secret" + string.Empty] ?? string.Empty;
            var tenantVal = configuration["Keyvault:Tenant" + string.Empty] ?? string.Empty;

            var audienceId = configuration.GetValue<string>(audienceVal) ?? string.Empty;
            var client_id = configuration.GetValue<string>(clientIdVal) ?? string.Empty;
            var client_secret = configuration.GetValue<string>(secretVal) ?? string.Empty;
            var tenantId = configuration.GetValue<string>(tenantVal) ?? string.Empty;

            string authorityUri = $"{authBaseURL}{tenantId}/oauth2/v2.0/authorize";
            string grant_type = grantTypeStr;
            string scope = $"{scopeStr}";
            var list = new List<KeyValuePair<string, string>>();
            var values = new Dictionary<string, string>()
                {
                    { "client_id", client_id },
                    { "scope", $"{client_id}/.default" },
                    { "client_secret", client_secret },
                    { "grant_type", grant_type },
                    { "resource", client_id },
                    { "audience", audienceId }
                };

            list.AddRange(values);
            var content = new FormUrlEncodedContent(list);
            var request = new HttpRequestMessage
            {
                Method = HttpMethod.Post,
                RequestUri = new Uri(authorityUri),
                Content = content
            };

            request.Content.Headers.ContentType = new MediaTypeWithQualityHeaderValue(contentType) { CharSet = "UTF-8" };
            var clt = new HttpClient();
            var result = clt.PostAsync(authorityUri, content);
            var resultContent = result.Result.Content;
            var bearerData = resultContent.ReadAsStringAsync().Result;
            var bearerToken = JObject.Parse(bearerData)["access_token"].ToString();

            return bearerToken;
        }
    }
}

How to get / generate access token from azure OAuth 2.0 token (v2) endpoints?