A null attribute key was converted to an unknown member. Attribute: %{Property/} of Dimension: %{Dimension/} from Database: ...

A null attribute key was converted to an unknown member. Attribute: %{Property/} of Dimension: %{Dimension/} from Database: %{Database/}, %1[Cube: %{Cube/}, Measure Group: %{Detail/}, Partition: %{Partition/}, %]Record: %ld{Record/}.