SAP Message /SAPPCE/DPCM1554 - You cannot clear down payments for DP chains with other documents

Diagnosis
You are trying to clear a down payment belonging to a down paymentchain, with another document, for example a down payment request orinvoice.
You can only clear a down payment with another down payment. Such downpayments must belong to the same down payment chain.

System Response
Processing was cancelled.

Procedure
Only select down payments. Note that all down payments that you want toclear must belong to the same down payment chain.