The authority was deemed unable to prove it has a five-year housing land supply by the Planning Inspectorate.
It comes after the Planning Inspectorate found that calculations made by staff at the council had been overestimated by up to a quarter.
The advice comes from council officers after an inspector ruled that the land set aside for new homes in the region had been overestimated by up to a quarter.
The finding comes as part of an appeal that was dismissed by the Planning Inspectorate – a national body that has the final say when applicants are unhappy with outcomes from councils.