bolt-js: Bolt Api's `client` methods are unresponsive

Description

Hello I am running into a problem that is preventing my slackbot from responding to slack commands.

To give a bit of background, I am using Javascript Bolt API combined with ExpressReceiver to deploy my app via Aws Lambda.

Although I set up the installation store properly for my ExpressReceiver as instructed, when I try to use app.command is seems that the client methods don’t work. For example, upon calling the client.conversations.join, the app just hangs. I checked the logs and there are no error, it just hangs…

Here’s my code for reference:

const { App, ExpressReceiver, LogLevel } = require("@slack/bolt");
const serverlessExpress = require("@vendia/serverless-express");

const expressReceiver = new ExpressReceiver({
    signingSecret: process.env.SLACK_SIGNING_SECRET,
    clientId: process.env.SLACK_CLIENT_ID,
    clientSecret: process.env.SLACK_CLIENT_SECRET,
    stateSecret: "my-secret",
    scopes: [
      "chat:write",
      "commands",
      "channels:join",
      "channels:history",
      "chat:write",
      "chat:write.public",
      "groups:history",
      "im:history",
      "mpim:history",
      "reactions:write",
    ],
    installationStore: {
        // I do all the proper setting, fetching, and deletion to my database here
    },
  });

const app = new App({
    receiver: expressReceiver,
    processBeforeResponse: true,
    logLevel: LogLevel.DEBUG,
    installerOptions: {
      directInstall: true,
    },
  });

app.command("/partypoll", async ({ ack, say, body, client }) => {
    console.log("got to /partypoll", ack, say, body, client);
    
    await ack();

    // Code execution hangs after the following line
    await client.conversations.join({ channel: body.channel_id });
    // Further logic here to create polls goes here, but code execution never reaches this point
  })

  module.exports.handler = serverlessExpress({
    app: expressReceiver.app,
  });
  

Do you happen to know the best way to get through this hanging behavior so I can properly make my slack app respond to commands successfully?

What type of issue is this? (place an x in one of the [ ])

• bug
• enhancement (feature request)
• question
• documentation related
• example code related
• testing related
• discussion

Requirements (place an x in each of the [ ])

• I’ve read and understood the Contributing guidelines and have done my best effort to follow them.
• I’ve read and agree to the Code of Conduct.
• I’ve searched for any related issues and avoided creating a duplicate issue.

---

Bug Report

Reproducible in:

package version:

{
  "name": "party-poll-v2",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT",
  "dependencies": {
    "@slack/bolt": "^3.12.1",
    "@slack/oauth": "^2.5.4",
    "@vendia/serverless-express": "^4.10.1",
    "axios": "^1.1.3",
    "querystring": "^0.2.1"
  },
  "devDependencies": {
    "serverless-dotenv-plugin": "^4.0.2",
    "serverless-offline": "^10.0.2"
  }
}

node version: v14.20.1 OS version(s): macOS Big Sur 11.6.8 (20G730)

Steps to reproduce:

1. To to slackbot website
2. Select “Add to Slack”
3. Authorize
4. Try running a party poll command, i.e. /partypoll "What is your favorite color?" red blue green

Expected result:

User sees slackbot respond and post a poll as a message to the channel

Actual result:

User’s command disappears. The slackbot is unresponsive. To the user, it appears as if nothing happened.