I want to preview PDF in google docs. I use 'http://docs.google.com/gview?url=mypdfurl'.I try to access pdf using localhost http connection. Sometime it is working fine and after some time It gives error "Whoops There was a problem to preview this document". I try many things like clear cache and cookie and also try other browser and incognito. I don't want to show this messages to my clients. So any hint or idea about it.