Melee attire coffer not opening

[ShinobiHayato]

Hi I obtained a Melee attire coffer from the last Monk quest in ARR. However I am not able to open it. I am trying to open it in a city btw. The message I get is saying I can't have more then 1 of the same items but I never had this before what does this mean exactly? Could use help understanding this and what I must do. Any help will be appreciated thank you.

[Tseng_the_Turk]

I don't know if the quest still rewards it, but do you perhaps have a "Hero's Belt of Striking" or whatever it would be called still in your inventory or Armory? That item is unique and may be preventing the box from opening.

[ManuelBravo]

You can only open them in mayor cities see the description of which ones and can only have one of each unique item.

[Aladire]

You could also put the items you have for the monk on a retainer that might match any potential items and then try to open it. This is how I am able to have 2 phoenix downs. You should be able to Google for what items are in the chest from the monk quest.