Specify a plant for the customer in the Customer General Data tab

What causes this issue?

You have not maintaned a plant for this customer (business partner). To
save ETM Data for a recipient with the specified reference category, you
must maintain the plant.

System Response

The system displays an error message and does not let you proceed.

How to fix this error?

Proceed as follows:
Choose the <LS>General Data</> pushbutton
Go to the <LS>Customer General Data</> tab
In the <LS>Additional General Data</> group box, specify the <LS>Plant
</>

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.