Xamarin Forms HttpClient Multipart/FormData returns 403 Forbidden - xamarin.forms

Question

I'm trying to make chat app with XamarinForms and I'm trying to upload a file with parameters to server. But I'm getting always 403 Forbidden message. (There is no authentication, there is only token key for now).
If I try to get or send any data to server, it works as well. When I try to send a file with data it returns 403 Forbidden message. I also tried to send same data with Postman. it's worked as well. I'm writing part of code, Could you please tell me, I made it wrong where?
Thanks in advance.
private async Task<HttpClient> GetClient()
{
HttpClient client = new HttpClient();
client.DefaultRequestHeaders.Add("Accept", "application/json");
client.DefaultRequestHeaders.Add("X-Token-Key", ServiceToken);
client.DefaultRequestHeaders.UserAgent.Add(new System.Net.Http.Headers.ProductInfoHeaderValue("Chrome", "41.0.2228.0"));
return client;
}
If I send text message, it works as well.
public async Task<MobileResult> SendConversationTextMessage(MessageModel message)
{
HttpClient client = await GetClient();
string param = JsonConvert.SerializeObject(message);
var response = await client.PostAsync(Url + "conversation/message_add_text", new StringContent(param, Encoding.UTF8, "application/json"));
var mobileResult = JsonConvert.DeserializeObject<MobileResult>(await response.Content.ReadAsStringAsync());
return mobileResult;
}
If I send message with data, it returns 403 Forbidden
public async Task<MobileResult> SendConversationFileMessage(
FileModel FileMessage,
int UserRemoteId,
int ConversationId,
int ToUserId,
string SendedTime,
MessageModel.MessageType Type,
MessageModel.MessageStatus Status,
string MessageType)
{
HttpClient client = await GetClient();
string PostUrl = Url + "conversation/message_add_" + MessageType;
MultipartFormDataContent content = new MultipartFormDataContent();
ByteArrayContent baContent = new ByteArrayContent(FileMessage.BinaryData);
StringContent UserIdContent = new StringContent(UserRemoteId.ToString());
StringContent ConversationIdContent = new StringContent(ConversationId.ToString());
StringContent ToUserIdContent = new StringContent(ToUserId.ToString());
StringContent SendedTimeContent = new StringContent(SendedTime.ToString());
StringContent TypeContent = new StringContent(Type.ToString());
StringContent StatusContent = new StringContent(Status.ToString());
content.Add(baContent, "AttachedFile", FileMessage.Name);
content.Add(UserIdContent, "serId");
content.Add(ConversationIdContent, "ConversationId");
content.Add(ToUserIdContent, "ToUserId");
content.Add(SendedTimeContent, "SendedTime");
content.Add(TypeContent, "Type");
content.Add(StatusContent, "Status");
try
{
var response = await client.PostAsync(PostUrl, content);
string result = await response.Content.ReadAsStringAsync();
var mobileResult = JsonConvert.DeserializeObject<MobileResult>(result);
return mobileResult;
}
catch (Exception e)
{
return new MobileResult
{
Result = false,
Data = null,
Message = e.ToString()
};
}
}
Postman-Screenshot
Edit: I've tested to send multipart/form-data different way but result is same I'm writing below code:
MultipartFormDataContent content = new MultipartFormDataContent();
var UserIdContent = new StringContent(UserId.ToString());
UserIdContent.Headers.Add("Content-Disposition", "form-data; name=\"UserId\"");
UserIdContent.Headers.Remove("Content-Type");
content.Add(UserIdContent, "UserId");
var ConversationIdContent = new StringContent(ConversationId.ToString());
ConversationIdContent.Headers.Add("Content-Disposition", "form-data; name=\"ConversationId\"");
ConversationIdContent.Headers.Remove("Content-Type");
content.Add(ConversationIdContent, "ConversationId");
var ToUserIdContent = new StringContent(ToUserId.ToString());
ToUserIdContent.Headers.Add("Content-Disposition", "form-data; name=\"ToUserId\"");
ToUserIdContent.Headers.Remove("Content-Type");
content.Add(ToUserIdContent, "ToUserId");
var SendedTimeContent = new StringContent(SendedTime.ToString());
SendedTimeContent.Headers.Add("Content-Disposition", "form-data; name=\"SendedTime\"");
SendedTimeContent.Headers.Remove("Content-Type");
content.Add(SendedTimeContent, "SendedTime");
var TypeContent = new StringContent(Type.ToString());
TypeContent.Headers.Add("Content-Disposition", "form-data; name=\"Type\"");
TypeContent.Headers.Remove("Content-Type");
content.Add(TypeContent, "Type");
var StatusContent = new StringContent(Status.ToString());
StatusContent.Headers.Add("Content-Disposition", "form-data; name=\"Status\"");
StatusContent.Headers.Remove("Content-Type");
content.Add(StatusContent, "Status");
var streamContent = new StreamContent(file.InputStream);
streamContent.Headers.Add("Content-Disposition", "form-data; name=\"AttachedFile\"; filename=\"" + file.FileName + "\"");
streamContent.Headers.Add("Content-Type", "video/mp4");
content.Add(streamContent, "AttachedFile", file.FileName);