There is a bug in PS/NA right now in Stonefalls where sometimes you click the chest and the portal doesn't appear. I spent a bit of time last night playing with it and it seems to be a problem with companions. If I unsummon my companion I have no trouble. I can get in just fine and then summon the companion just fine. For my sorcerer, I had to unsummon both pets and move to the second bar with no pet skills.
As a workaround someone else can click the chest and make a portal that others (not grouped) can use.
I submitted a bug report in-game but haven't heard any response.
PS5/NA