Exchange rate & differs from rate set & by & %

What causes this issue?

You have entered the exchange rate &V1(C)& to translate the amounts to
local currency.
In the Customizing system of Financial Accounting, however, the
exchange rate is set at &V2(C)&.

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?

Please check the exchange rate &V1(C)&, and make any necessary
corrections. If you want to post the invoice at the exchange rate set
in the Customizing system, delete your entry in the field <LS>Exchange
rate</>.

Error message extract from SAP system. Copyright SAP SE.