Diagnosis
In the Customizing under Financial Accounting (New) -> AccountsReceivable and Accounts Payable -> Business Transactions -> Debit-Sideand Credit-Side Down Payment Chains -> Enhance Debit-Side andCredit-Side Down Payment Chains -> Assign Chain Type to Item Categoryfor Sales Documents you have defined an entry for the company codeV2 and item category v1 of the sales order.
This means you have defined the integration of the sales order and thedebit-side down payment chain for this company code and item category.When creating a sales order with this item category, the systemautomatically creates a contract of a debit-side down payment chain.
The system does not allow you to create a contract of a debit-side downpayment chain for this using the maintenance transaction for downpayment chains (transaction /SAPPCE/DPCD01 - Debit-Side Down PaymentChains).

System Response
The system does not allow you to create a contract with reference tothis sales order.