Protractor / Selenium XHR stays in status "pending"

I'm using protractor with selenium to test my Angular page. At some random points, it justs stops the execution because an XHR-Request is still "pending" (in Chrome Dev Tools). When I copy the request URL (it is a simple GET request) and open it in a new tab, it immediately returns the data (JSON, ~200 chars long).

The request stays "pending" when executing the E2E tests, and out of 10 times the said GET-URL gets called it fails maybe 1 time.

Selenium prints the following error: "Timed out receiving message from renderer: 298.388".

Any idas?