There’s no reason a rapport chest should have an item level requirement, so I assume it’s a bug. Additionally, 1430 is an extremely high item level for our stage of the game, so no one can open it right now, and most people won’t be able to open it for a long time.
To explain why 1430 is insane, as if any requirement makes sense:
The cap of T3 chaos dungeon and normal mode Punika abyss dungeon gear is 1370. That’s hard cap at +15, there is no +20 option on that gear. At 1370, you can do Punika’s hard mode abyss dungeon, which lets you craft legendary gear that can upgrade to +20, and you need to upgrade that gear to +16 average (past the +15 soft cap) to reach 1430 to open this chest.
Seems like a tall order to me.