How does an Out of Network provider get loaded into BCBS IL system for claims processing?

Our provider group is out of network with BCBS Illinois. One of our practitioners saw a BCBS IL member using OON benefits and we are trying to bill for these services. However, the claims keep on rejecting, stating "PA BILLING NPI IS NOT ON FILE, "PA RENDERING NPI IS NOT ON FILE", and "PA BILLING NPI IS NOT AUTHORIZED FOR TAX ID". How do we correct this?