Hello Vinod Kumar Reddy,
The error refers to that you have missed out to select the warehouse in the PO itself.
In addition to what Satish and André mentioned; please note the below points in this regard.
--- The item which you selected in the PO, must be a stocked item for which selecting warehouse is a mandatory thing.
--- Then check in Product information management > Setup > Dimension and variant groups > Storage dimension groups. In this form; both site and warehouse must be activated like below.

--- Then check in the All Products and product masters OR Released products form for that item (which you selected in the PO line); you will find that this storage dimension group is selected there which is validating both Site and Warehouse.

Next step: -
--- Edit the PO
--- Select the warehouse in every single lines in this PO if already removed (applicable only for lines where stocked items are selected).
--- Confirm the PO.
--- Do the product receipt.
Kindly check and provide your feedbck.
Best regards,
Sourav Dam
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