Plant & is not assigned to a sales organization

What causes this issue?

The error analysis of the defective record found that an assignment of
the plant to the sales organization is missing. This means that the
plant is not valid for sales.

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?

If you no longer need the assignment, please delete the line.
Otherwise, maintain the assignment of plants to sales organizations.
Then start the assignment again.

Error message extract from SAP system. Copyright SAP SE.