Business partner of plant &1 has no customer in target system

What causes this issue?

You want to distribute plant data using the data replication framework
(DRF).
The business partner that is assigned to this plant is available in the
target system, but has no customer assigned.

System Response

It is only possible to replicate data for a plant to a target system
where the assigned business partner already exists with all required
roles (customer and, if required, supplier).

How to fix this error?

Transfer the business partner data before you transfer the plant data.
If the business partner data has been transferred before, use
<DS:TRAN.SRT_MONI>Web Service Utilities: Message Monitor</> and
<DS:TRAN.MDS_PPO2>Postprocessing Desktop</> to check whether any errors
occurred during the check of the role-specific data. Correct these
errors and transfer the plant again.

Procedure for System Administrators

The data transfer settings for business partners and plants must be
defined so that the business partner data is transferred before the
plant data.
If you set up direct transfer for both business partner data and plant
data, you can use optional retry parameters for the transfer of the
plant data and adjust the wait time so that the business partner data is
replicated to the target system before the transfer of the plant data
finishes.

Error message extract from SAP system. Copyright SAP SE.