Erratum to: Search for dark matter produced in association with a leptonically decaying Z boson in proton?proton collisions at s = 13 Te (The European Physical Journal C, (2021), 81, 1, (13), 10.1140/epjc/s10052-020-08739-5) - Sirunyan AM; Tumasyan A; Adam W; Bergauer T; Dragicevic M; Erö J; Valle AED; Frühwirth R; Jeitler M; Krammer N; Lechner L; Liko D; et al. (European Physical Journal c, 2021)