TeamsBot onMessage not getting triggered

Question

Context: I am creating a simple Teamsbot (The complete stripped down version template, that simply echoes back what it gets as message), with JavaScript.

The JavaScript (Node.js Backend) server is hosted on Azure and I have my default domain URL (which works as I can test some API endpoints through Postman).

The issue: when I upload my appPackage.zip file and do "Preview in Teams", It does not echoes back anything, neither does the onMessage() gets triggered at all. After logging I can see that the endpoint "/api/messages" is not getting hit at all.

Question: How do I make my teams app hit the endpoint /api/messages and trigger TeamsBot.onMessage()

Below is my index.js.

const restify = require("restify");

const {
    CloudAdapter,
    ConfigurationServiceClientCredentialFactory,
    ConfigurationBotFrameworkAuthentication,
} = require("botbuilder");
const {TeamsBot} = require("./teamsBot");
const config = require("./config");

// Create adapter
const credentialsFactory = new ConfigurationServiceClientCredentialFactory(
    config
);

const botFrameworkAuthentication = new ConfigurationBotFrameworkAuthentication(
    {},
    credentialsFactory
);

const adapter = new CloudAdapter(botFrameworkAuthentication);

adapter.onTurnError = async (context, error) => {
    console.error(`\n [onTurnError] unhandled error: ${error}`);

    // Only send error message for user messages, not for other message types so the bot doesn't spam a channel or chat.
    if (context.activity.type === "message") {
        // Send a message to the user
        await context.sendActivity(
            `The bot encountered an unhandled error:\n ${error.message}`
        );
        await context.sendActivity(
            "To continue to run this bot, please fix the bot source code."
        );
    }
};

// Create the bot that will handle incoming messages.
const bot = new TeamsBot();

// Create HTTP server.
const server = restify.createServer();
server.use(restify.plugins.bodyParser());

const port = 443;

// Listen on proper port
server.listen(port, () => {
    console.log(`\nBot server listening on port ${port}`);
});

// Main bot message endpoint
server.post("/api/messages", async (req, res) => {
    console.log("Received request at /api/messages:", {
        type: req.body.type,
        text: req.body.text,
        timestamp: new Date().toISOString(),
    });

    try {
        await adapter.process(req, res, async (context) => {
            await bot.run(context);
        });
    } catch (error) {
        console.error("Error processing message:", error);
        res.status(500).json({
            error: "Error processing message",
            details: error.message,
        });
    }
});

// Health check endpoint
server.get("/health", async (req, res) => {
    res.json({
        status: "healthy",
        timestamp: new Date().toISOString(),
    });
});

// Diagnostic endpoint
server.get("/api/config", async (req, res) => {
    res.json({
        botId: process.env.BOT_ID ? "Configured" : "Missing",
        tenantId: process.env.BOT_TENANT_ID ? "Configured" : "Missing",
        appType: process.env.BOT_TYPE ? "Configured" : "Missing",
        port: port,
        nodeVersion: process.version,
    });
});

// Gracefully shutdown HTTP server
[
    "exit",
    "uncaughtException",
    "SIGINT",
    "SIGTERM",
    "SIGUSR1",
    "SIGUSR2",
].forEach((event) => {
    process.on(event, () => {
        server.close();
    });
});

Below is my teamsBot.js.

const {TeamsActivityHandler, TurnContext} = require("botbuilder");

class TeamsBot extends TeamsActivityHandler {
    constructor() {
        super();

        this.onMessage(async (context, next) => {
            console.log("Running with Message Activity.");
            console.log("Message received:", context.activity.text); // Log the incoming message
            const removedMentionText = TurnContext.removeRecipientMention(
                context.activity
            );
            const txt = removedMentionText
                .toLowerCase()
                .replace(/\n|\r/g, "")
                .trim();
            await context.sendActivity(`Echo: ${txt}`);
            // By calling next() you ensure that the next BotHandler is run.
            await next();
        });

        // Listen to MembersAdded event, view https://docs.microsoft.com/en-us/microsoftteams/platform/resources/bot-v3/bots-notifications for more events
        this.onMembersAdded(async (context, next) => {
            const membersAdded = context.activity.membersAdded;
            for (let cnt = 0; cnt < membersAdded.length; cnt++) {
                if (membersAdded[cnt].id) {
                    await context.sendActivity(
                        `Hi there! I'm a Teams bot that will echo what you said to me.`
                    );
                    break;
                }
            }
            await next();
        });
    }
}

module.exports.TeamsBot = TeamsBot;

As part of my manifest.json in appPackage zip file, here is the configuration.

{
    "$schema": "https://developer.microsoft.com/en-us/json-schemas/teams/v1.17/MicrosoftTeams.schema.json",
    "version": "1.0.0",
    "manifestVersion": "1.17",
    "id": "<some_id>",
    "name": {
        "short": "testbot2",
        "full": "testbot2"
    },
    "staticTabs": [
        {
            "entityId": "conversations",
            "scopes": ["personal"]
        },
        {
            "entityId": "about",
            "scopes": ["personal"]
        }
    ],
    "bots": [
        {
            "botId": "<bot_id_here>",
            "scopes": ["personal", "team", "groupChat"],
            "isNotificationOnly": false,
            "supportsCalling": false,
            "supportsVideo": false,
            "supportsFiles": false
        }
    ],
    "validDomains": [
        "<azure_domain_url_without_https>"
    ],
    "webApplicationInfo": {
        "id": "<microsoft_client_(app)_id_here>",
        "resource": "<azure_hosted_domain_url_with_https>"
    },
    "devicePermissions": ["notifications"],
    "defaultGroupCapability": {
        "team": "bot",
        "groupchat": "bot",
        "meetings": "bot"
    }
}

Also I have added other permissions in the manifest.json. Thank you.

Question: How do I make my teams app hit the endpoint /api/messages and trigger TeamsBot.onMessage() ?