The Oracle Management Server (OMS) host and port specified via OMS_HOST and EM_UPLOAD_PORT is not available

Error :  The Oracle Management Server (OMS) host and port specified via OMS_HOST and EM_UPLOAD_PORT is not available. Pass in a valid hostname and port number for the OMS to successfully deploy the agent.

Solution :

In order to resolve above error, you should add hostnames and ip addresses of OMS Server and Agent Server to the both server's /etc/hosts file.

OMS host # vi /etc/hosts

xx.xx.xx.xx agent_host

AGENT host # vi /etc/hosts

xx.xx.xx.xx oms_host

After that, test it with ping 

OMS host # ping agent_hostname

AGENT host # ping OMS_hostname

Cheers !