I was trying to add a database in cloud control 12c. I clicked on Targets -> database -> add. Then select a hostname. But the next screen doesn't have item found (no database found). I checked the server and the agent is running. I also upload and secure agent. Also tried stop and start agent a couple of times. What else I should try? I used same way added a couple other databases but dont know why this one doesnt work. Your help is appreciated. (BTW, a listener is discovered.)
Did you install the agent and the database using same user?
and the primary group of the user owning database should be same as the primary group of the user who installed the agent.
Also please see
How To Manually Add Database Targets in 12C Cloud Control [ID 1371846.1]