This is not advanced troubleshooting and does not address mis-configurations. But, if your OEM agent is not communicating with OMS – try this.
cd to the place where “emctl” lives.
./emctl stop agent
./emctl clearstate agent
Note: everyonce in a while – I’ll see java “errors/messages” and java appears to be doing garbage collection – so “clearstate” may have to be done more than once.
./emctl start agent
./emctl upload agent
What if you don’t know where the OEM agent is installed – what is the path?