You need to add to the input an additional flag:

charge=1

or

you can define the wavefunction for rhf

rhf;wf,nelectron,nirrep,nspin

or

uhf;wf,nelectron,nirrep,nspin

and carefully with the symmetry if you define the wavefunction, because the index of the wanted irrep is tricky (if you use this, then check the symmetry treatment of Molpro)