Guild Wars 2

Does anyone know what I’m doing wrong with this puzzle? I’m in the chest room, the box already looks like it’s open. I climb up to stand on the pressure plate to crumble the wall but nothing happens. Can anyone help?

From the Wiki:

If the chest is open when you reach the section with the journal, you will be unable to trigger the matriarch event that enables the pressure plate, which will prevent you from reaching the final spot. Wait awhile and the chest will eventually close and you’ll be able to complete the puzzle.

Wait for the chest to reset.