Azure PubSub Listener Serverless Function works when run locally, fails when run in Azure

I have a web site app that generates a simple object with 4 props. It posts to an Azure Serverless Function A. Function A takes the post, and sends it to an Azure PubSub instance running in Azure. I have a second Serverless Function B, which is subscribed to the PubSub. When it gets the original object, it writes it to Cosmos MongoDB. I have a 3rd Serverless Function C which the web site app uses to read the data back from Mongo DB.
I run the web site, Function A, Function C, and of course the PubSub all in Azure.
When I run Function B (the PubSub Listener) inside of Code editor locally, the entire set of apps works perfectly. However when I push Function B up to Azure, Function B is "hearing" the messages from PubSub, but it is failing to write to Mongo. I have included a combined screen shot of the PubSub trace tool, showing a successful session running Function B locally, and under that, is the image of the trace tool showing when I run Function B on Azure. Seems like either [a] I am missing some setting needed to run Fucntion B on Azure, or Function B is allowed to post to Mongo when running locally but nor when running in Azure. For the Function B in Azure I have the CORS setting set to *
Is there an allowed client IP setting somewhere in Cosmos such as MongoDB Atlas has?

here is the Function B code:

module.exports = function(context, req) {
    const WebSocket = require('ws');
    const { WebPubSubServiceClient } = require('@azure/web-pubsub');
    const MongoClient = require('mongodb').MongoClient;
    
  
    const connect = async () => {
      client = await MongoClient.connect('connection string' );
                                          
      return client;
      }
  
    main();
  
    async function main() {
      const hub = "kurtpubsub.webpubsub.azure.com";
      var connectionString = "Endpoint=https://kurtpubsub.webpubsub.azure.com;AccessKey= key";
      let serviceClient = new WebPubSubServiceClient(connectionString, hub);
      let token = await serviceClient.getClientAccessToken();
      let ws = new WebSocket(token.url);
      ws.on('open', () => console.log('connected'));
      ws.on('message', data => {

       let newRecord = JSON.parse(data);
        // got the data, now write to mongo
      
        // have to wait for 2nd promise to get he client object
        connect().then( console.log("connected to mongo"))
        .then((client) => { writeDB(client, newRecord)});
        //console.log(newRecord);
      });
    }
  
    function writeDB(client, pNewRecord)
    {
      try {
        const database = client.db("restdb");
        //context.log("connected to DB successfully");
          // Insert a single document
          
          database.collection('restaurants').insertOne(pNewRecord);
          //client.close();
        } catch (err) {
          console.log(err.stack);
          client.close();     // Close connection if app is dying
        }
    }
  }
  

Here is the host.json file:

{
  "version": "2.0",
  "logging": {
    "applicationInsights": {
      "samplingSettings": {
        "isEnabled": true,
        "excludedTypes": "Request"
      }
    }
  },
  "extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle",
    "version": "[3.*, 4.0.0)"
  }
}

Here is the function.json file:

{
  "bindings": [
    {
      "authLevel": "anonymous",
      "type": "httpTrigger",
      "direction": "in",
      "name": "req",
      "methods": [
        "get",
        "post"
      ]
    },
    {
      "type": "http",
      "direction": "out",
      "name": "res"
    }
  ]
}