SEVERE: Connection details provided as OMS_HOST and EM_UPLOAD_PORT is not active when installing OEM agent in silent mode

Recently I stuck into this issue, and the solution was not provide FQDN of OMS server in the response file (parameter OMS_HOST). It turned out that agent installer try to resolve it adding the domain name to FQDN. The installation performed by agentpush method from OMS server.

Worse to note, that agentpush operation from agent host (via emcli) do not throw such error when OMS_HOST=FQDN_of_OMS. So take care about it ! :)