An entry already exists for sequence number &1 in document buffer

What causes this issue?

Check payments are added to table DPAYCHKH/DPAYCHKP to enable a simple
assignment of the check or document number in the case of external check
number assignment.
On the creation of an entry for the payment media run, the system
determined that there is already an entry for bank account &V2& at bank
&V1&. The existing entry has sequential number (DLFNR) &V3& and
therefore you cannot add this entry.

System Response

You cannot add any entries of this run to the table.

How to fix this error?

To receive the entries, determine the cause of the error, and once you
have removed this, start a new payment media run with report <LS>
SAPFKPY3</>.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.