Blocking not possible. Open purchase requisition exists

What causes this issue?

You want to block asset &V1& &V2&. However, open purchase requisitions
still exist for this asset.

System Response

You cannot block the asset.

How to fix this error?

If you still want to block the asset, you must correct the asset
account assignment for the purchase requisition
or
you must cancel the purchase requisition.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.