Unable to reference the fields from other table in measure calculations

Question

I want to calculate average height of floor in a building but i'm unable to reference the other fields in measure calculations.

I downloaded the pbix file with the average measure, it works perfectly fine whereas when I try to replicate exact same calculation in fresh file, it does not recognize the fields.

Please see below the screenshots:
(with answer)

(when i try to replicate)

Answer 1

This question is related to Power BI, not Power Query. Please post it over in the Power BI Community forum.