Websocket ERR_CERT_AUTHORITY_INVALID on Java Spring + vanila JS

Question

Trying to reproduce an example from Kurento tutorial "Group Call". Server is starting, but when i try to connect using websockets it shows error:

conferenceroom.js:18  WebSocket connection to 'wss://localhost:8443/gg' failed: Error in connection establishment: net::ERR_CERT_AUTHORITY_INVALID

Here's my main application class:

@SpringBootApplication
@EnableWebSocket
public class DemoApplication implements WebSocketConfigurer {
    @Bean
    public UserRegistry registry() {
        return new UserRegistry();
    }

    @Bean
    public RoomManager roomManager() {
        return new RoomManager();
    }

    @Bean
    public CallHandler groupCallHandler() {
        return new CallHandler();
    }

    @Bean
    public KurentoClient kurentoClient() {
        return KurentoClient.create();
    }

    @Bean
    public ServletServerContainerFactoryBean createServletServerContainerFactoryBean() {
        ServletServerContainerFactoryBean container = new ServletServerContainerFactoryBean();
        container.setMaxTextMessageBufferSize(32768);
        return container;
    }
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
    
    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        registry.addHandler(groupCallHandler(), "/gg").setAllowedOriginPatterns("*").withSockJS();
    }

}

And client JS code which shows an error:

var ws = new WebSocket('wss://' + "localhost:8443" + '/gg');
var participants = {};
var name;

window.onbeforeunload = function() {
    ws.close();
};

ws.onmessage = function(message) {
    var parsedMessage = JSON.parse(message.data);
    console.info('Received message: ' + message.data);

    switch (parsedMessage.id) {
    case 'existingParticipants':
        onExistingParticipants(parsedMessage);
        break;
    case 'newParticipantArrived':
        onNewParticipant(parsedMessage);
        break;
    case 'participantLeft':
        onParticipantLeft(parsedMessage);
        break;
    case 'receiveVideoAnswer':
        receiveVideoResponse(parsedMessage);
        break;
    case 'iceCandidate':
        participants[parsedMessage.name].rtcPeer.addIceCandidate(parsedMessage.candidate, function (error) {
            if (error) {
              console.error("Error adding candidate: " + error);
              return;
            }
        });
        break;
    default:
        console.error('Unrecognized message', parsedMessage);
    }
}

function register() {
    name = document.getElementById('name').value;
    var room = document.getElementById('roomName').value;

    document.getElementById('room-header').innerText = 'ROOM ' + room;
    document.getElementById('join').style.display = 'none';
    document.getElementById('room').style.display = 'block';

    var message = {
        id : 'joinRoom',
        name : name,
        room : room,
    }
    sendMessage(message);
}

function onNewParticipant(request) {
    receiveVideo(request.name);
}

function receiveVideoResponse(result) {
    participants[result.name].rtcPeer.processAnswer (result.sdpAnswer, function (error) {
        if (error) return console.error (error);
    });
}

function callResponse(message) {
    if (message.response != 'accepted') {
        console.info('Call not accepted by peer. Closing call');
        stop();
    } else {
        webRtcPeer.processAnswer(message.sdpAnswer, function (error) {
            if (error) return console.error (error);
        });
    }
}

function onExistingParticipants(msg) {
    var constraints = {
        audio : true,
        video : {
            mandatory : {
                maxWidth : 320,
                maxFrameRate : 15,
                minFrameRate : 15
            }
        }
    };
    console.log(name + " registered in room " + room);
    var participant = new Participant(name);
    participants[name] = participant;
    var video = participant.getVideoElement();

    var options = {
          localVideo: video,
          mediaConstraints: constraints,
          onicecandidate: participant.onIceCandidate.bind(participant)
        }
    participant.rtcPeer = new kurentoUtils.WebRtcPeer.WebRtcPeerSendonly(options,
        function (error) {
          if(error) {
              return console.error(error);
          }
          this.generateOffer (participant.offerToReceiveVideo.bind(participant));
    });

    msg.data.forEach(receiveVideo);
}

function leaveRoom() {
    sendMessage({
        id : 'leaveRoom'
    });

    for ( var key in participants) {
        participants[key].dispose();
    }

    document.getElementById('join').style.display = 'block';
    document.getElementById('room').style.display = 'none';

    ws.close();
}

function receiveVideo(sender) {
    var participant = new Participant(sender);
    participants[sender] = participant;
    var video = participant.getVideoElement();

    var options = {
      remoteVideo: video,
      onicecandidate: participant.onIceCandidate.bind(participant)
    }

    participant.rtcPeer = new kurentoUtils.WebRtcPeer.WebRtcPeerRecvonly(options,
            function (error) {
              if(error) {
                  return console.error(error);
              }
              this.generateOffer (participant.offerToReceiveVideo.bind(participant));
    });;
}

function onParticipantLeft(request) {
    console.log('Participant ' + request.name + ' left');
    var participant = participants[request.name];
    participant.dispose();
    delete participants[request.name];
}

function sendMessage(message) {
    var jsonMessage = JSON.stringify(message);
    console.log('Sending message: ' + jsonMessage);
    ws.send(jsonMessage);
}

and my application.properties:

# ----------------------------------------
# WEB PROPERTIES
# ----------------------------------------
server.port=8443
server.ssl.key-store=classpath:keystore.jks
server.ssl.key-store-password=123
server.ssl.key-password=123

I've tried to change links on client side from localhost to 127.0.0.1 and my public IP according to same problem solution. Switching from wss to ws on client side didn't help too. It started showing 404 and 400 errors.

Also, i tried to reproduce an example and had the same error.

After all i created certificate using keytool using guide from kurento and it didn't help.

I would appreciate any advise.