I have a server with a database that was added to EM 13c. Now we added another database on the serve

We created another database on a Server and I'm trying to add the second database to EM 13c. I can add the database to EM 13c but EM shows it down. (red). I never get to the prompts where we can add the agent for the second database. In Settings I go to Add Target -> Add Targets Manually -> Install Agent on Host. I get the error "Unable to proceed as a host target already exists for the provided host name. Remove the host names that are already being monitored by Enterprise Manager." Is there another method to follow