Fileupload not working through API in c#

Fileupload not working through API in c#

Hi, 

Using the below UploadFile function, trying to upload a document. But receiving the error: {"ERROR":"Invalid URL specified !!"}.

What correction is required to upload the document successfully.

public async Task<string> UploadFile()
        {
            var retunVal = "";
            using (HttpClient httpClient = new HttpClient())
            {
                using (HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, @" https://apidocs.zoho.com/files/v1/upload?authtoken=ed4eef708508749dcd63f38b7307xxxx&scope=docsapi"))
                {
                    request.Properties.Add("filename", "Untitled.jpg");

                    using (FileStream fstream = File.Open(@"C:\Users\jharikrishna\Desktop\Untitled.jpg", FileMode.Open))
                    {
                        request.Properties.Add("content", fstream);

                        retunVal = await (await httpClient.SendAsync(request)).Content.ReadAsStringAsync();
                    }
                }
            }

            return retunVal;
        }