If you are receiving a Silverlight Application Storage Error with code N8007 using Mozilla Firefox, you might check TomTaylormsft’s post on Silverlight.net for troubleshooting information. If the three listed links all work it may be as “simple” as disabling Private Browsing mode. To accomplish this, head to Options -> Privacy and “Use custom settings for History”. Obviously not ideal, but a simple toggle to enable watching Netflix. If you really do not wish to modify this setting, you may consider running a separate browser (such as Chrome) specifically for Netflix.

TL;DR

Private browsing kills Netflix.