Enter a valid country

What causes this issue?

You have entered country key "&V1&" which could not be found defined in
table T002 as a valid key.

How to fix this error?

Press F4 to display a list of valid country keys and select one of
these or delete all entries in the field.
If you need a new country key, please maintain one in the Customizing
table T002.

Error message extract from SAP system. Copyright SAP SE.