title: Microsoft Bot Framework: broadcast messages to users from database
body: <p>Situation: When a user registers for a bot (by entering a message to the bot, I store the information of that user in a database:
  - UserId
  - UserName,
  - ServiceURL</p>
  
  <p>At some point in time I want to have my bot broadcast a message to all the users in that table.</p>
  
  <pre><code>foreach (var bUsers in users)
  {
  MicrosoftAppCredentials.TrustServiceUrl(bUsers.ServiceUrl);
                          MicrosoftAppCredentials creds = new MicrosoftAppCredentials("&lt;&lt;appid&gt;&gt;", "&lt;&lt;secret&gt;&gt;");
                          var connector = new ConnectorClient(new Uri(bUsers.ServiceUrl), creds);
                          var conversationId = await connector.Conversations.CreateDirectConversationAsync(new ChannelAccount(), new ChannelAccount(bUsers.UserId, bUsers.UserName));
                          message = Activity.CreateMessageActivity();
                          message.From = botAccount;
                          message.Recipient = userAccount;
                          message.Conversation = new ConversationAccount(id: conversationId.Id);
                          message.Text = "Hello from " + context.Activity.From.Name;
                          message.Locale = "en-Us";
                          var reply = await connector.Conversations.SendToConversationAsync((Activity) message);
  }
  </code></pre>
  
  <p>With this code, I get a message saying: </p>
  
  <blockquote>
    <p>Invalid conversation ID in teamsChannelId</p>
  </blockquote>
  
  <p>I don't understand this message, and is it even possible to do what I want?</p>