Per your help article: "If there have been no announcements concerning this Error Code by @BungieHelp, please post a thread in the #Help forum detailing your experience." I was trying to leave the Tower to go to the Sunken Isles to get the Mysterious Box for my Hunter from the Volundr Forge area. If it helps or makes any difference, the Tower instance I was in was adjusted for my Dad's character that just finished the Red War campaign. He could still see Cayde and there was no Iron Banner on the platform. Probably completely irrelevant, but its the only thing I could think of that was different from any other time. He logged off a while ago, though. Not sure if him leaving my fireteam and me not being in an instance for my character (completed Forsaken, Lvl 50, PL649) might cause unexpected results.