... No numbering concept has been assigned to country &

What causes this issue?

A numbering concept has not been assigned to the company code country.
Withholding tax types exist that are relevant to numbering. The system
cannot determine a certificate number because the Customizing settings
are incomplete.

System Response

Payment cannot be made.

How to fix this error?

Assign a numbering concept to the company code country.

Error message extract from SAP system. Copyright SAP SE.