The records are already being processed by &

What causes this issue?

DEFINE &USER& = &V1&
INCLUDE MESSAGE_ENQUEUE_USER OBJECT DOKU ID TX
You want to process data records that are already being processed by
user &V1&. To prevent users from overwriting each other's work, the
system has locked the data records.

System Response

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

How to fix this error?

Wait until user &V1& has finished processing the data records.
Alternatively, contact user &V1&.

Error message extract from SAP system. Copyright SAP SE.