Unable to check the name of the target server

What causes this issue?

When a background job is scheduled, you can specify a target computer.
This then determines, on which computer the job is executed. The name
used is checked for certain criteria.
This message indicates that this check was attempted, but could not be
completed. The reason for this is that the list of currently active SAP
systems could not be generated.

System Response

This message was then issued. Correct the target computer name. Please
note that you can also leave this field blank. The system load will
then determine, on which computer the job is executed.

How to fix this error?

Check whether the SAP system is logged on to the SAP message server, or
whether the message server is active. Use transaction sm51 and check
the list displayed whether the SAP system is in the list. If this list
cannot be generated, notify your system administrator, who will be able
to solve the problem.

Error message extract from SAP system. Copyright SAP SE.