I ran into this issue while changing my VM's configuration. The VM is a Windows XP machine that I use primarily to watch Netflix on Linux, since Netflix doesn't support Linux. After I made a change to the VM configuration, I could no longer view Netflix videos. The error code was N8156-6013 and the error message said that my system date was not valid, even though it was completely correct.
Examining the issue, I found that some solutions point to a file in the C:\ProgramData folder. This folder doesn't exist in my XP VM. XP keeps the file in:
c:\Documents and Settings\All Users\Application Data\Microsoft\PlayReady\
The file is mspr.hds. All you have to do is rename that file. If you get an error while trying to rename it, close out any browser that has Netflix running on it. After you have successfully renamed the file, you should be able to watch your Netflix again.