After posting encoded data ,I got this resut <QueryDict: {'{"username":"test","password":"test","error_msg":""}': ['']}> This is my code let loginData = LoginModel(username:email, password: password,error_msg: "")     let encoder = JSONEncoder()     guard let encoded = try?encoder.encode(loginData)else{       print("fail to encode")       return     }           print(String(data: encoded, encoding: .utf8))     print("ok")     var request = URLRequest(url: url)     request.httpMethod="POST"     request.addValue("application/json", forHTTPHeaderField: "Accept")     request.httpBody = encoded what should I do?