  In this work we prove a prime number type theorem involving the normalised
Fourier coefficients of holomorphic and Maass cusp forms, using the classical
circle method. A key point is in a recent paper of Fouvry and Ganguly, based on
Hoffstein-Ramakrishnan's result about the non-existence of the Siegel zeros for
$GL(2)$ $L$-functions, which allows us to improve preceding estimates.
