Grid Control : The database target is currently unavailable. The state of the components are listed below

Problem

Applied patch on 1 instance of 4-node RAC database. Patch was successful.
When logged into grid control, It shows status of database instance up but no details in it. Message "The database target is currently unavailable. The state of the components are listed below" is displayed.
All other 3 instances(where no patch applied) were fine.

Actions

emctl status agent
--It shows "Agent is Running and Ready"

emctl upload agent
--It shows "EMD upload completed successfully" and 0 pending uploads

Solution

emctl clearstate agent
Message "EMD clearstate completed successfully" will be displayed

Verify in Grid Control. Problem resolved!