TypeError: Cannot read property 'Symbol(Symbol.iterator)' of undefined
<p>I get the following exception when a web service request fails.</p>

<pre><code>TypeError: Cannot read property 'Symbol(Symbol.iterator)' of undefined
</code></pre>

<p>Specifically the HTTP GET returns 400 Bad request.</p>

<p>Here you can find the involved component:</p>

<pre><code>@Component({
    selector: 'events-list',
    directives: [EventRow],
    changeDetection: ChangeDetectionStrategy.OnPush,
    providers: [HTTP_PROVIDERS],
    template: `
&lt;table&gt;
    &lt;tr *ngFor="let event of events | async" [event]="event" &gt;
    &lt;/tr&gt;
&lt;/table&gt;
  `
})
export class EventsList implements OnInit {
    events: Observable&lt;Event[]&gt;;

    constructor(public http: Http) { }

    ngOnInit(): void {
        let obs;
        this.events = Observable
            .create((o) =&gt; {
                obs = o;
                obs.next();
            })
            .flatMap(() =&gt; {
                return this.http.get('event/view');
            })
            .retryWhen(error =&gt; {
                error.delay(3000);
            })
            .map((response: Response) =&gt; {
                setTimeout(() =&gt; {
                    obs.next();
                }, 10000);
                return (&lt;any&gt;response.json()).map(item =&gt; {
                    return item;
                });
            });
    }
}
</code></pre>

<p>Any suggestion?</p>

<p>Thanks in advance!</p>