Unable to Validate Zoom Webhook (Serv2ServOAuth) with N8N

Hi, I cannot validate any webhooks from our Zoom App (Srv 2 Srv OAuth) since last week.
It would fail the auto validation occasionally, but I usually could manually validate it from the Zoom App settings after 2-3 attempts. Now I cannot validate any other the webhooks anymore.

I do not see any errors, and I have confirmed the Hash created is correct.

We use N8N for the webhook endpoint. It is receiving the webhook fine, hashing the Token using our Secret and then returning that plus the plain token in Json, and code 200 as a response to the webhook.

Has anything changed recently (within the last 2 weeks) that may be impacting this?
I reached out to support at Zoom, but they told me they couldnt assist and to try here instead.

Any assistance would be amazing!

@tech6 here is a sample code that worked for me:

app.post('/webhook', (req, res) => {
  const webhookEvent = req.body.event;
  if (webhookEvent === 'endpoint.url_validation') {
    const plainToken = req.body.payload.plainToken;
    const hashedToken = crypto.createHmac('sha256', ZOOM_WEBHOOK_SECRET_TOKEN)
    const responseJson = {
      plainToken: plainToken,
      encryptedToken: hashedToken
  } else {
    // Handle other webhook events here
    console.log('Received webhook:', req.body);

    // Send a response to acknowledge the webhook