EDI error - Inbound Sales order, Error Customer XX not valid for Sales org

I am just new in my role and am tyrying to correct a few errors for all the inbound EDI orders from customers.

I think it is something to do with the buying group..but i have no idea where to look

Customer 0000401757 not valid for Sales Org. 0000401757 1, Dist. Chan. NWS1 , Grp 01

Message no. ZEDI012

Diagnosis

The customer could not be derived using the Sales Area and SC Buying Group combination.

Procedure

Make sure the customer is assigned to the correct Sales Area and SC Buying Group.

Any ideas?