System failure when calling function &1 on RFC dest. &2

What causes this issue?

The system tried to call a function on a remote destination. The
function call failed. The failure may be due to one of the following:
A runtime error in the function module in the destination system
An incorrect RFC destination definition
Release inconsistencies, for example, function not available on the
remote system or interface is incompatible

System Response

The call is not executed. Expected processes or results may not be
correct.

How to fix this error?

Check the RFC destination settings and the function availability and
interface.

Procedure for System Administrators

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.