Problem : When trying to create Customers in SAP for newly created Sales Areas, you will get errors saying ” Sales Area XXXX/YY/ZZ not defined for customers” . For example, in the picture below , we just created a new sales area ( HPUS/EC/LP ) and tried to create a customer in that sales area.
Solution: This problem occurs in cases where there are common distribution channels / divisions associated with the sales org. Go to [ spro -> IMG -> Sales & Distribution ->Master Data -> Common Distribution Channels and Divisions ] and you can see that the distribution channel EC is assigned to common distribution channel 01.
The easiest solution in this case is to remove the entry HPUS/EC assigned to 01