Judgment of the Court (Seventh Chamber) of 29 September 2022.#FS v Chief Appeals Officer and Others.#Request for a preliminary ruling from the High Court (Irlande).#Reference for a preliminary ruling – Social security for migrant workers – Regulation (EC) No 883/2004 – Coordination of social security systems – Family benefits – Back payment – Relocation of the beneficiary to another Member State – Article 81 – Concept of ‘claim’ – Article 76(4) – Duty of mutual information and cooperation – Non-compliance – 12-month limitation period – Principle of effectiveness.#Case C-3/21.