Twilio client JavaScript SDK fails to initialize

Question

I am try to initialize Twilio SDK using a Twilio JWT Token.
Below is my code:

<script type="text/javascript" src="https://<path>/twilio.min.js">
<script type="text/javascript">

const token = "my-jwt-token";

const options = {
 "debug": true,
 "warnings": true,
 "logLevel": 1,
 "region": '<default>'
};

let device = new Twilio.Device(token, options); 

await navigator.mediaDevices.getUserMedia({ audio: true });

device.audio.availableOutputDevices.forEach(function (device, id) {
  console.log('device.label: ', device.label); // I can see devices listed 
});

device.on('incoming', function(call) {
  console.log('New incoming: ', call);
});

device.on('error', function(error) {
  console.log('Error: ', error);
});

device.on('registered', function() {
  console.log('Device registered');
});

device.on('ready', function (device) {
  console.log('Twilio Device Ready: ', device);
});

device.register();

// I am able to hear sound playing in the browser
// For both of these tests
device.audio.ringtoneDevices.test();
device.audio.speakerDevices.test();


</script>

I am getting below errors:

ERROR #1: 
code: 31009
message: "No transport available to send or receive messages"

ERROR #2: 
code: 31204
message: "JWT token is missing in request."

I have verified the JWT token and it is valid, it does work in other Twilio SDK without any issue.

Version of Twilio JavaScript SDK: 1.9.1
Browser: Google Chrome Version 105.0.5195.125

Do we require to call device.register()?
If I don't call device.register() I don't get errors and I see event ready is called.
But in any case I don't get incoming call event.