On PvE, who can open chests in a house with a Tool Cupboard? Why can't I loot someone's chest on PvE?

On PvE servers, storage inside a building protected by a Tool Cupboard (TC) is locked to that cupboard's players.

Only the cupboard owner and the players authorized on it can open those chests - others can't loot them

If a teammate can't open your chests, authorize them on the Tool Cupboard.

A chest outside any cupboard's range isn't protected this way.