I also have the same problem with no content loading. Roku was fine yesterday, 10.11. Today nothing loads. Version 11.0.0 build 4193-AE was deployed this morning, 10.12 at 00:58:42.
It’s obvious the system updates broke Roku and need to be reverted back to the prior version until these updates pass QA. A big step that was missed.
A lot of us rely upon Roku only since cutting the cable cord. Please make this a critical priority and fix it ASAP!