public async Task <string> Register(Guid token) { MessengerLink link = await _botRepository.GetLinkByAuthToken(token); if (link.UserId.HasValue) { return("You are already registered!"); } string domainName = User.Identity.Name; UserInfo ttUser = _usersApp.GetUserInfo(domainName); if (ttUser != null) { await _botRepository.RegisterUser(ttUser.Id, ttUser.Email, token); return("Successfully registered!"); } return($"No user with domain name '{domainName}' in TimeTracker"); }