It's an FAA mandated safety issue.
It's a regulatory thing about the seat power. All the 737-900s are offline. There is some maintenance action that needs to happen that is safety related.
https://www.reddit.com/r/AlaskaAirli..._is_down_wifi/
might have started last wends, I got a 6am email about a 7am flight and since then the notice has come much further in advance