Orders for the source of supply XXXX stil exist. No deletion

Hi,

We are trying to delete the Production Data Structure for all elements of a material in transaction /SAPAPO/CULL_RTO_DELL. But when we execute the deletion, we are receiving the error below:

We checked the product view (/SAPAPO/RRP3) and found out that there was an open Planned Order. But I don't think this is an issue because there was an instance that we could delete the PDS of a material even though there is an open planned order.

Thanks.