Since yesterday around noon, I can't get into a Vanguard or Crucible playlist, and I don't see any other players in the Tower or in any missions. Nothing about my network has changed, and it was working perfectly until then. I'm not getting an error message, it just sits on the Searching/Evaluating Guardians screen forever when I try to play a multiplayer game type. My Xbox One is online, with an open NAT, and all of its system network checks come back fine.