Httpclient POST request not working properly

Question

   [FunctionName("Function1")]
    public static async Task<IActionResult> Run(
        [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
        ILogger log)
    {
        log.LogInformation("C# HTTP trigger function processed a request.");
        var data = new { key = key, id = req.Query["mailid"] };
        var result = await myHttpClient.PostAsJsonAsync("https://someapi.com/api/info", data);

        return new OkObjectResult(result);
    }

Hi. Im trying to build an azure function, which gets the variable mailid and sends a POST request to an API with the apikey and the mailID in a body, so it can check the status of the mail and give back if its delivered or not. I dont get it to work and "result" returns a json of the httpClient, with the error code 500. Why doesnt the request work? The API expects the key and id in a JSON format in the POST-body.

Answer 1

[FunctionName("Function1")]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
            ILogger log)
        {
            log.LogInformation("C# HTTP trigger function processed a request.");
            string mailid = req.Query["mailid"];
            var data = new Dictionary<string, string> {
                { "key", key },
                { "id", mailid },
            };
            //var data = new { key = key, id = req.Query["mailid"] };
            var json = JsonConvert.SerializeObject(data, Formatting.Indented);
            var stringContent = new StringContent(json);
            myHttpClient.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
            var result = await myHttpClient.PostAsync("https://someapi.com/api/info", stringContent);
            var responseString = await result.Content.ReadAsStringAsync();

            return new OkObjectResult(responseString);
        }

I just got it to work without an anonymous type variable, which the senior advised me to use. This gets me the result I wanted. It seems like it didnt get send in the proper post-body, as a proper json.