That is not an issue with gateway/emunand. The Netflix application has never worked. I have tried on 3 different new 3ds both with latest firmwares and w/ eshop spoofing and downloading directly from eshop on sysnand.
The issue is with the netflix application directly, I believe that netflix themselves have stopped to provide support to the 3ds app. I have had this issue..always.. I uninstall the app. reinstall. it allows me to log in and access the movies with out issues. They dont load so i have to exit and enter again, to find that this time It will not allow me to log in.... Same issue for months and no workaround.