Conversion exit &1 could not be found

What causes this issue?

Conversion exist &V1& could not be found.

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?

Import the conversion exit from the source system, if the relevant
technical prerequisites are fulfilled, or implement your own conversion
exit, by implementing the function modules CONVERSION_EXIT_XXXXX_INPUT
and CONVERSION_EXIT_XXXXX_OUTPUT.
You can find templates for the conversion exits, for example, in
function modules CONVERSION_EXIT_ALPHA_INPUT and CONVERSION_EXIT_AL
PHA_OUTPUT.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.