I am getting message: '(#100) No matching user found', when using the facebook messenger bot sample tutorial code

Question

When using the same Facebook getting started guide (https://developers.facebook.com/docs/messenger-platform/quickstart)

I am getting an error on the node.js console when typing a message and sending it to the bot.

   { error: 
      { message: '(#100) No matching user found',
        type: 'OAuthException',
        code: 100,
        fbtrace_id: 'BLguK1o+VsH' } } } 

I have the latest version of node.js and am using Ngrok to expose my local host.

My app.post routine is below: (It is an exact copy of the getting started guide)

router.post('/webhook', function (req, res) {
  var data = req.body;

  // Make sure this is a page subscription
  if (data.object == 'page') {
    // Iterate over each entry
    // There may be multiple if batched
    data.entry.forEach(function(pageEntry) {
      var pageID = pageEntry.id;
      var timeOfEvent = pageEntry.time;

      // Iterate over each messaging event
      pageEntry.messaging.forEach(function(messagingEvent) {
        if (messagingEvent.optin) {
          receivedAuthentication(messagingEvent);
        } else if (messagingEvent.message) {
          receivedMessage(messagingEvent);
        } else if (messagingEvent.delivery) {
          receivedDeliveryConfirmation(messagingEvent);
        } else if (messagingEvent.postback) {
          receivedPostback(messagingEvent);
        } else {
          console.log("Webhook received unknown messagingEvent: ", messagingEvent);
        }
      });
    });

    // Assume all went well.
    //
    // You must send back a 200, within 20 seconds, to let us know you've 
    // successfully received the callback. Otherwise, the request will time out.
  //  res.sendStatus(200);
  }
}); 

Here is the receivedMessage function that is being called

function receivedMessage(event) {
  var senderID = event.sender.id;
  var recipientID = event.recipient.id;
  var timeOfMessage = event.timestamp;
  var message = event.message;

  console.log("Received message for user %d and page %d at %d with message:", 
    senderID, recipientID, timeOfMessage);
    console.log(JSON.stringify(message));


  var messageId = message.mid;

  // You may get a text or attachment but not both
  var messageText = message.text;
  var messageAttachments = message.attachments;

  if (messageText) {

    // If we receive a text message, check to see if it matches any special
    // keywords and send back the corresponding example. Otherwise, just echo
    // the text we received.
    switch (messageText) {
      case 'image':
        sendImageMessage(senderID);
        break;

      case 'button':
        sendButtonMessage(senderID);
        break;

      case 'generic':
        sendGenericMessage(senderID);
        break;

      case 'receipt':
        sendReceiptMessage(senderID);
        break;

      default:
        //getArticles(function(err,articles){
        //  sendTextMessage(senderID, articles[0].text);
        //});     
        sendTextMessage(senderID, messageText);

       /* client.converse('my-user-session-42', messageText, {})
            .then((data) => {
                console.log('the question asked :' + messageText);
            sendTextMessage(senderID, data.msg);    
            console.log('Yay, got Wit.ai response: ' + JSON.stringify(data));
        }).catch(console.error);
        */


    }
  } else if (messageAttachments) {
    sendTextMessage(senderID, "Message with attachment received");
  }
}

Further more here are my require statements:

const bodyParser = require('body-parser');
var express = require('express');
var request = require('request');
var router = express.Router();
const fetch = require('node-fetch');
const {Wit, log} = require('node-wit');

Here is the rest of the functions used:

function sendTextMessage(recipientId, messageText) {
  var messageData = {
    recipient: {
      id: recipientId
    },
    message: {
      text: messageText
    }
  };

  callSendAPI(messageData);
}

function callSendAPI(messageData) {
  request({
    uri: 'https://graph.facebook.com/v2.6/me/messages',
    qs: { access_token: PAGE_ACCESS_TOKEN },
    method: 'POST',
    json: messageData

  }, function (error, response, body) {
    if (!error && response.statusCode == 200) {
      var recipientId = body.recipient_id;
      var messageId = body.message_id;

      console.log("Successfully sent generic message with id %s to recipient %s", 
        messageId, recipientId);
    } else {
      console.error("Unable to send message.");
      console.error(response);
      console.error(error);
    }
  });  
}

So I read somewhere that it all has to do with page ids or the way that facebook processes ints but I'm a little confused.

Any help would be much appreciated.

Answer 1

This error occurs because the incorrect token is being used to send messages back to the bot. Ensure you have the correct one (even by hard-coding it at first), which can be copied from your developers.facebook.com page under Messenger -> Settings -> Token Generation.