It's the same for me...I tried all possible options described in multiple forums and topics...switching character and trying to complete the bounties and offering the boon of opulence but I cannot place the banner to open the door. To be precise, I do not have the option to hold X and place the banner on the right side circle of the tribute hall's door...if I join with other players they can go through but the door is closed for me. At this point I need help on this one or possible support.