CELEX:62021CA0003: Case C-3/21: Judgment of the Court (Seventh Chamber) of 29 September 2022 (request for a preliminary ruling from the High Court (Ireland) — Ireland) — FS v The Chief Appeals Officer, The Social Welfare Appeals Office, The Minister for Employment Affairs, The Minister for Social Protection (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)