I have used signalr 2.4.0 library for display the real time data.I have invoked one method from server and then listener call automatically and send ticket count to me.It's work on chrome.safari and Mozilla but It is not working on IE11. On IE11 listener not call and we are not getting the real time ticket count.

invoked the method
signalRInit(eventId, alternateKey) {
        try {
            const hub = this.testService.getEventRegHub();
            hub.invoke('testEvent', Key, eventId);
        } catch (err) {
            console.log("error");
        }
    }

Call listener for getting real time data:this is not work on IE11 but work on other browser

const hub = this.testService.getEventRegHub();
        hub.on('testListner', (abc, TixAvailableToPublic) => {
            if (this.ref == abc) {
                this.remainingEventTickets = EventTixAvailableToPublic;
                this.isOrAre = this.remainingEventTickets > 1 ? 'are'  'is';
                this.ticketWordForRemainingTickets = this.remainingEventTickets > 1 ? 'tickets'  'ticket';
            }
        });