Unable to determine exchange rate on & & & &, even after adjustment

What causes this issue?

No entry exists in the exchange rate table for the specified date,
currency pair and exchange type. A routine has been selected in the
calculation rules screen (No Exg Rt. Handling) to control this case.

System Response

The system is unable to determine an exchange rate for the given
currency pair and exchange type, even after adjusting the date to find
an exchange rate on an earlier date. A pricing error is generated.

How to fix this error?

An entry must exist in the table if the error routine is selected in
the calculation rules screen. Either make an entry in the table or use
a different routine.
Follow the menu path in Customizing: Global Settings -> Currencies ->
Enter Exchange Rates (transaction OB08).

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.