Adobe Sign refresh token Issue - getting error The underlying connection was closed Hello All, I am using the developer account and trying to get access token using refresh token but getting underlying connection close error -below is the code we are trying -string requestURI = "https://secure.in1.adobesign.com/oauth/v2/refresh";string refreshToken = refresh token;var requestBody = new List<KeyValuePair<string, string>>(){ new KeyValuePair<string, string>("client_id", Client id), new KeyValuePair<string, string>("client_secret", client_secret), new KeyValuePair<string, string>("grant_type", "refresh_token"), new KeyValuePair<string, string>("refresh_token", refreshToken),};using (var httpClient = new HttpClient()){ HttpContent requestContent = new FormUrlEncodedContent(requestBody); httpClient.DefaultRequestHeaders.Clear(); var httpResponse = httpClient.PostAsync(requestURI, requestContent).Result; var response = httpResponse.Content.ReadAsStringAsync().Result;}below is the error details -System.Net.Http