Hi,
Can you please past the full SM21 screen shot.
Have you configured remote system for eg in DBAcockpit.....etc..
When this system was started the another remote system was not started at that time.
Is this message still appearing in the logs..
Do you use DNS or host file.
Can you also check the below note.
25941 - SAP System does not find host name of
Thanks
Rishi Abrol