Hello Nayeem,
Is there any other agents registered to this solman? (Maybe your solman is not reachable from other servers. gw/acl_mode = 1)
What about agent admin link? Can you see your SMD agents on AgentAdmin screen?
Can you try below links
https://scn.sap.com/blogs/lsalvador/2013/05/31/scripts-for-manually-setup-diagnostics-agents
Regards,
Yuksel AKCINAR