You will need to contact your ISP or do further troubleshooting, leaving on a public DNS is not the solution and will lead to further issues
A note in support of Vazandrew here, Google DNS is not a solution, it may appear to help but will likely make other things work more slowly too, at best it's a temporary solution.
Thanks, I'll stay tuned for the proper fix, pardon my ignorance but Netflix is working for now so yahoo!
Without reading through the whole thread again, I'm pretty sure someone has already given you a proper fix, get the proper DNS settings from your ISP.
They gave me googles universal DNS 008 008 008 008, this not proper because it is public? Perhaps they will figure out a proper one in future...
Double tap the home button... flick up all the open apps.... restart Netflix...
Worked for me
EDIT (to my last post): Unfortunately, the error persisted. Still, you can try my "fix" and see if you're lucky.
Netflix error code 11800 ATV4