2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/69802We present a counterexample to the conjecture on the homotopy invariance of configuration spaces. More precisely, we consider the lens spaces $L_{7,1}$ and $L_{7,2}$, and prove that their configuration spaces are not homotopy equivalent by showing that their universal coverings have different Massey products.6 pagesAlgebraic Topology55R80; 55S30text