Well Edgar,
let's see then in spro
Logistics Execution->Shipping->Deliveries->Define Reasons for Blocking in Shipping
Check out the configuration of your delivery block reason and pay special attention to this instruction:
"In sales documents, you can either enter delivery blocks manually at header level (business data in the sales document header) or they can be proposed automatically by the system. In the latter case, the delivery block must be entered in the respective sales document type (see chapter
"Define sales document types"). In addition, the delivery block in the sales document header is only effective if the delivery block has been assigned to the respective delivery type."
It must be something in the configuration of the delivery block reason you're using.
Regards,
Edgar