“…Along with all the works, where this operator appears, we found [2,6,12] where the fractional Ambrosetti-Prodi type problem is studied, but not in the periodic setting that is the objective of the manuscript at hand. It is fair to mention that not much is known of the existence of periodic solutions in problems that involve the fractional Laplacian (see [3,4,9,11]). In the local case, s = 1, the seminal work is the one of Ambrosetti and Prodi [1], where the nonlinearity crosses the first Dirichlet eigenvalue.…”