Roku Smart TV/Netflix Issue

I'm not sure if this might fit better under TV, but since the devices in question are WiFi, here goes:

I've got four devices that are not able to get past the logo screen for Netflix: two Sony smart TVs and two (different model) Rokus.  On the occasion when they do get past that screen, I'll get an error code, and I've gotten three different ones on the four devices.  Netflix works fine on phone and laptop, and all other channels/apps work on the devices.  Signal strength tests as "excellent."  I've spent several hours troubleshooting both on my own and on the phone with Netflix support, with no success, so I'm wondering if it might be network-related.  Is anyone else having a similar problem, and has anyone found a solution?