ASP.Net Web API: Send object with token and get result from server

Hi!

I created API, but now I want send object with token and get result from server. Maybe my code is wrong I can't get result from server side. Here my code:

public List<string> Get_Application()
{
    List<string> applicationList = new List<string>();
    applicationList.Add("30");
    applicationList.Add("0");
    applicationList.Add("Consumer");
    applicationList.Add("Dushanbe");
    applicationList.Add("South West Region");
    applicationList.Add("7000");
    applicationList.Add("10");
    applicationList.Add("1");
    applicationList.Add("22");
    applicationList.Add("0.10");
 
    var client = new RestClient($"https://192.168.0.21:4455/api/Test/InsertUser/?{applicationList}&token=CBNL6vHAT8Q2d2rxfpUFrjk012Kgm89j");
    client.Timeout = -1;
    var request = new RestRequest(Method.POST);
    var json = JsonConvert.SerializeObject(applicationList);
    request.AddHeader("Content-Type", "application/json");               
    request.AddParameter("application/json", json, ParameterType.RequestBody);
    IRestResponse response = client.Execute(request);
 
    return applicationList;
}

// Model Data Fields
namespace TestAPI.Models
{
    public class Data
    {
        [JsonPropertyName("age")]
        public string age { get; set; }
 
        [JsonPropertyName("gender")]
        public string gender { get; set; }
 
        [JsonPropertyName("sector")]
        public string sector { get; set; }
 
        [JsonPropertyName("district")]
        public string district { get; set; }
 
        [JsonPropertyName("region")]
        public string region { get; set; }
 
        [JsonPropertyName("amount")]
        public string amount { get; set; }
 
        [JsonPropertyName("duration")]
        public string duration { get; set; }
 
        [JsonPropertyName("credit_history_count")]
        public string credit_history_count { get; set; }
 
        [JsonPropertyName("int_rate")]
        public string int_rate { get; set; }
 
        [JsonPropertyName("threshold")]
        public string threshold { get; set; }
    }
 
    // Objects send to API
    public class SendToTest
    {
        [JsonPropertyName("token")]
        public string token { get; set; }
 
        [JsonPropertyName("data")]
        public Data data { get; set; }
    }
}
 
// Controller
 
namespace TestAPI.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class TestController : ControllerBase
    {
 
        [HttpPost("InsertUser")]// My problem between controller applicationList and token
        public async Task<ActionResult> PostToTest([FromBody] SendToTest sendToTest)
        {
            var url = "https://test.azurewebsites.net/api/testapi"; // I haven't problem with this line api because I sent data and token manual got result
            var client = new RestClient(url);
            var request = new RestRequest(url, Method.Get);
            request.AddHeader("Content-Type", "application/json");          
            request.AddParameter("application/json", JsonConvert.SerializeObject(sendToTest), ParameterType.RequestBody);  // Here I full data manual got result         
            RestResponse response = await client.ExecuteAsync(request);
            if (response.Content == null)
            {
                // Can this happen?
            }
            else
            {
                var testDeserializedClass = JsonConvert.DeserializeObject<ResponseFromTest>(response.Content);
                            
                return Ok();
            }
 
            return Ok();
        }
    }
}