OTBI - Product Management - Cross Subject Area Logical SQL giving Error

Summary

OTBI - Product Management - Cross Subject Area Logical SQL giving Error 'The selected request cannot be performed because it references an unknown subject area named'

Content

Hello,

I have created a very simple logical SQL, shown below. Can you please help me in understanding where am I doing the mistake.

SET VARIABLE ENABLE_DIMENSIONALITY = 1;
select SubjectArea1.Inventory_Item_id1, SubjectArea1.Item1, SubjectArea2.Inventory_Item_id2, SubjectArea2.Item_Class2, SubjectArea2.Item2
from (SELECT
   "Product Management - Source System Item Real Time"."Main"."Inventory Item Id" Inventory_Item_id1,
   "Product Management - Source System Item Real Time"."Main"."Item" Item1