mahjong on Nostr: Invalid reference

{ "id": "5b5d88c67c706aeb03ea891c2fdf35712b8e6d1eb6bdcfaebd7b9b5dbd1d0512", "pubkey": "5ac0427cf0588ae5c9f09aa800e99dbbe4dc19c16afbd322b94c016c085e1c0d", "created_at": 1687887631, "kind": 1, "tags": [ [ "e", "521567e480025ba154410816fad7196f25a387358a15549914a74bfe14e05134" ], [ "p", "897bb37449ed3fcea198e260a406733290dc2bedd5a5d447a68472c491baa739" ] ], "content": "Invalid reference", "sig": "4c41a5293351b3282c03b6a31b0678938abbebd63bc67f0a28a12fdf76a8fc140869f7ef817a8265192639f0a7cf1651266fa9400f1a7849c912e7c5d7a3a836" }