Unexpected Response 403 today with no changes to my app.

Today out of the blue my app stopped working and I receive 403 Unexpected Response when trying to connect to my AWS IoT custom endpoint (wss://staging.stream.mysite.com/mqtt).

When I check the logs for both my IoT custom authorizer function and my IoT lamba topicrule handler, both are empty.

I have made no changes to my app before this happened and am unsure of the cause so far.

I connect to the websocket endpoint using async-mqtt js library with a custom iot authorizer that parses the username and clientId fields to determine authorization.
https://github.com/mqttjs/async-mqtt

effectively like this:

const connection = yield mqtt.connectAsync('staging.stream.mysite.com/mqtt', {
  username: '?SDK=BrowserJSv2&Version=1.1.3&token=<auth_token>',
  clientId: 'ANONYMOUS::uuid',
})

Any ideas what could be wrong or why the sudden failure or how to debug?

Edit: Resolved on it's own after hours of breakage.

Edited by: phasetwo on May 11, 2020 1:19 PM

Edited by: phasetwo on May 11, 2020 3:56 PM