Entries with non-empty countries are obsolete

What causes this issue?

For this combination of account plan and transaction key, tax account
determination for each country has not been set.

System Response

Entries with a non-empty country are not taken into consideration for
tax account determination.

How to fix this error?

You should delete entries with a non-empty country.

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.