Housing Benefit- new address, not yet “registered”

My client was told that she cannot get (pension age) HB because her accommodation is not “registered”
I am not sure what “registered” means in HB terms (except maybe as HMO). Client is renting a room in a property. Property itself is fine, can be easily found as a postal address, but client’s room is not registered separately anywhere.
Can someone enlighten me about this “registration” problem? Is it perhaps an admin issue for the HB department- if they can’t find the property, they can’t pay for it?
Client has got tenancy agreement and the landlord is happy to cooperate with the LA. LL is a privately owned tenancy management group, does not reside with client. There are 5 rooms in the property. Property is registered as HMO.

sounds like the HB side want each room to have its own property ref to pay HB whereas ctax will just need 1 property ref because its a himo… def an admin issue for the LA rather than any real reason HB cant be awarded - i would suggest they make an award on he prop ref they have and then amend if each room is given a property reference.

Perfect, thank you so much Prisca.