Chat GPT API Help needed in C#

I am doing a simple API Call to ChatGPT API using C# in Dot Net Core 3.1 with below JSON Data, however the request is failing with response of Bad Request, Please help:

{“model”:“gpt-3.5-turbo”,“messages”:[{“role”:“system”,“content”:“You act as the middleman between USER and a DATABASE. Your main goal is to answer questions based on data in a SQL Server 2019 database (SERVER). You do this by executing valid queries against the database and interpreting the results to answer the questions from the USER.”},{“role”:“user”,“content”:“From now on, you will only ever respond with JSON. When you want to address the user, you use the following format {"recipient": "USER", "message":"message for the user"}.”},{“role”:“assistant”,“content”:“{"recipient": "USER", "message":"I understand."}”},{“role”:“user”,“content”:“You can address the SQL Server by using the SERVER recipient. When calling the server, you must also specify an action. The action can be QUERY when you want to QUERY the database, or SCHEMA when you need SCHEMA information for a comma-separated list of tables. The format you will use for requesting schema information is as follows {"recipient":"SERVER", "action":"SCHEMA", "message":"Person.Person, Person.Address"}. The format you will use for executing a query is as follows: {"recipient":"SERVER", "action":"QUERY", "message":"SELECT SUM(OrderQty) FROM Sales.SalesOrderDetail;"}”},{“role”:“user”,“content”:“The following tables are available in the database: UserMaster, ProductMaster, Customer_Order, ClientMaster. You will always first request the SCHEMA for a table before using the table in a QUERY. You need to make joins between tables”},{“role”:“user”,“content”:“Hello! How can I help you?”}],“max_tokens”:1500,“temperature”:0.7}

URL Used: <>/v1/completions

Getting Error for below code:
** Below is my C# Dot Net Core 3.1 Code**

        var searchParams = new
                model = "gpt-3.5-turbo",
                messages = conversationMessages,
                max_tokens = 1500,
                temperature =0.7

            //Converting the object to a json string
            string json = JsonConvert.SerializeObject(searchParams);

            //Needed to setup the body of the request
            StringContent data = new StringContent(json, Encoding.UTF8, "application/json");

            var url = <<OpenaiAPIURL>>/v1/completions;

            var request = new HttpRequestMessage(HttpMethod.Post, url);

            // Add the JSON content to the request
            request.Content = new StringContent(json, Encoding.UTF8, "application/json");

            var client = new HttpClient();

            client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", "API_KEY");

            // Send the HTTP request and get the response
            HttpResponseMessage response = client.SendAsync(request).GetAwaiter().GetResult();

            //It would be better to make sure this request actually made it through
            dynamic responseObject = JsonConvert.DeserializeObject(response.Content.ReadAsStringAsync().GetAwaiter().GetResult());

            string result = responseObject.Choices[0].Message.ToString();

Its resolved, the URL was incorrect