No changes were made overtly.

Both computers recently updated windows 10, but that didn't have any specific network setting changes detailed.

I'm able to log in if I use the "old" browser (the dark one prior to shadowbringers) as my launcher by changing the config file. Again, I've tried every internet explorer suggestion regarding resetting, enabling permissions, completely wiping cache etc.

I never use Explorer, so I'm not sure how that could have even changed state.