public async Task <ActionResult> Conversation(string groupId, string conversationId)
        {
            try
            {
                GraphServiceClient graphClient = GraphHelper.GetAuthenticatedClient();

                Conversation conversation = await GroupHelper.GetGroupConversation(groupId, conversationId);

                ViewBag.GroupId = groupId;
                return(View(conversation));
            }
            catch (ServiceException se)
            {
                return(RedirectToAction("Index", "Error", new { message = Request.RawUrl + ": " + se.Error.Message }));
            }
        }