nmax inconsistency

When running a geometry optimisation on a CH3 radical I am presented with the following error and the job fails

Error MP: nmax inconsistency 0 855 1 1 1 15

Error MP: nmax inconsistency 0 720 1 16

Error MP: nmax inconsistency 369 801 1 21

could anyone tell me the cause of this error and how to avoid it?