So I've been having this issue ever since I got my MBPR 15. Any google related sites/services such as youtube, gmail, and the default search bar, would sometimes not load on Safari throughout the day. Emptying the cache sometimes help and also turning the wifi on and off. This happens on every wifi network I'm connected to. It does not happen on Firefox, Chrome, or Opera. What can be causing this? I've also uninstalled all extensions and the problem still persist.