WSOD when visiting www.mysite.com

I recently moved from a shared host to Amazon Web Services and it appears to have created a problem where I (and all my visitors) get a WSOD when we enter the site url with the "www" prefix. (For example: "www.mysite.com" ) However, when we enter "mysite.com" or "www.mysite.com." (note the period at the end) the website loads as it should. I have checked all my DNS records but have been pointed towards WordPress. Do you have any idea what might be causing this? Right now we have a url redirect from "www.mysite.com" to "www.mysite.com." but I feel like this is not a long term solution... just a band aid. Any direction on this would be greatly appreciated.