Conversion of & to &, exchange rate type & on & is not possible

What causes this issue?

Overhead is always applied in controlling area currency.
If the "All currencies" option is active in this controlling area, the
amounts are also translated automatically to the currency of the
objects to be debited and credited.
The currency translation
for planning transactions uses the exchange rate type from the plan
version you are processing. If you do not enter a value date, the
system also takes the date from this plan version.
for actual transactions uses the average exchange rate (type "M") and
the value date you specify. If you do not enter a value date the system
takes the last day of the posting period.
The currency translation rate has not been maintained for the date
entered.

System Response

The object cannot be processed and the overhead cannot be posted.

How to fix this error?

Maintain the currency translation rates.

Error message extract from SAP system. Copyright SAP SE.