Function is not possible; RFC server group '&1' does not exist

What causes this issue?

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

System Response

How to fix this error?

Assign an RFC server group that has already been defined.
To process RFC groups, choose <LS>Tools > Administration, Management ->
Network -> RFC Destination, RFC -> RFC Groups</> or execute transaction
<DS:TRAN.RZ12>RZ12</>.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.