EM12c agent deployment fails with agent port passed by user is busy...

EM12c agent deployment fails with "ERROR: Agent Configuration Failed SEVERE: Agent port passed by user is busy and cannot proceed with the configuration. Pass a free port and retry the configuration.”
netstat -an doesnt show the port being in use and rerun of the deployment fails consistently with the same error.

In the end, it's the hostname mismatch issue where the hostname in '/etc/hosts' file is different to what's configured in '/etc/sysconfig/network'.

Once that's fixed by updating the entry in the network file, agent deployment succeeded.

This is another error that's not straight forward to resolve as nowhere as it gives an indication that there's a hostname conflict.