I am suddenly having the same issue. If I go into the preferences, select the Privacy tab and click on the Details button for the Cookies and other Website Data, I can search for and delete the msn.com cookie which allows me to then open msn.com. Problem is, after I close Safari and reopen, I am back to the same problem, the page does not load. Just a blank page. I have also noticed as others have mentioned, that when the page won't load, there is an icon of a yellow b to the left of www.msn.com and when I clear the cookie and successfully reload the page, there is a multicolored butterfly next to www.msn.com.
This appears to be the only website I am having issues with. Any thoughts are greatly appreciated.
I have also tried flushing the DNS cache as well as using alternate DNS addresses (208.67.222.222, 208.67.220.220 and 8.8.8.8, 8.8.4.4). Nothing at the moment seems to work other than deleting the cookie created by msn.com but this only works until then next time I reopen Safari.