Google docs sometimes returns blank page (about: blank)

The Google docs url https://docs.google.com/gview?url=Document_URL sometimes returns a blank page. It is random and when it happens you have to refresh it until it shows correctly the document (luckily it fails only a few times). It happens either by placing the url directly in the browser or by calling it from .jsp with "response.sendRedirect (URL)" which is my case. Any solution or someone knows the reasons? Thank you