Ever since I set up my sisters new/used MacMini, Netflix movies stop loading at 98% and then show error code N8156-6023. The Netflix support site is useless and suggests a network problem where in fact it is a problem with Silverlight. After checking my network setup over and over again, I found that the solution was to delete a file called “mspr.hds” located in /Library/Application Support/Microsoft/PlayReady/. You can find this solution a little hidden away on the Apple Support Communities site posted by iCare here: https://discussions.apple.com/thread/3937926?start=0&tstart=0
Thank you iCare and Happy Netflixing!