No city numbers exist for postal code &1 in country &2

What causes this issue?

There are several records in the table ADRPCDCITY for the postal code.
However there are no records in the table ADRCITY for the city numbers
entered there (i.e. the cities do not exist) -> data inconsistency.

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?

Error message extract from SAP system. Copyright SAP SE.