Clear your DNS settings if your using chrome.
Press Ctrl + F5
Worked for me. (Thanks to Blinky)
If you're using chrome, it tends to be pretty broken.. I had the same problem. Clearing my DNS fixed it until I refreshed or closed and re-opened it and posed the same issues over and over again.
I decided to uninstall chrome and go back to firefox, which doesn't give me any problems.