diff --git a/plugins/MRCC_Utils/amplitudes.irp.f b/plugins/MRCC_Utils/amplitudes.irp.f
index 48c8b7d7..6f3d2b0c 100644
--- a/plugins/MRCC_Utils/amplitudes.irp.f
+++ b/plugins/MRCC_Utils/amplitudes.irp.f
@@ -89,7 +89,8 @@ END_PROVIDER
  double precision               :: phase
  logical                        :: ok
  integer, external              :: searchDet
- 
+
+ PROVIDE psi_non_ref_sorted_idx 
 
  !$OMP PARALLEL default(none) shared(psi_non_ref, hh_exists, pp_exists, N_int,&
      !$OMP   active_excitation_to_determinants_val, active_excitation_to_determinants_idx)&