Credit check not OK (automatic credit control)

What causes this issue?

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

System Response

The results of the automatic credit check are not OK and the items that
were checked now have the status "Credit check not OK".
The system blocks subsequent processing of this document, such as
creating deliveries or invoices, and sends it to the employee
responsible for approving documents blocked for credit reasons. After
clarifying the credit status of this customer, he or she can choose to
release some or all items.
Single log of the credit check:

How to fix this error?

Error message extract from SAP system. Copyright SAP SE.