I had had this error on my Mcafee Epolicy Orchestrator server for a few weeks and did not realise how much of a problem this error actually is never mind how to fix it.
If you see this error check the last time that your agents on your servers or clients last checked in, you will find that they have not checked in since this error started. This means no new systems deployed or updated, pretty serious!
You will also see the Mcafee Epolicy Orchestrator service 5.x.x has not started either, this is an apache related service.
Mcafee Epolicy Orchestrator Ports
To cut a long story short, Mcafee Epolicy runs on Apache web server on on various ports.
| Agent Handler to ePO Server | TCP | 8444 |
| Agent to Server Port | TCP | 80 |
| Agent to Server Secure | TCP | 443 |
| Agent Wake up | TCP | 8081 |
| Agent Broadcast | TCP | 8082 |
| Console to ePO (management) | TCP | 8443 |
| Client to Server (secure) | TCP | 8444 |
| Security Threats comms port | TCP | 8801 |
| ePO to SQL | TCP | 1433 |
What had happened is that a new service had been installed into IIS on the same port (port 443 in my example), because of this when the server had been rebooted, IIS started before Apache and the service could not start correctly.
To resolve this issue log into the IIS console on your Epolicy server and make sure that no websites clash with any of the above ports, mainly 80 and 443. You can check this via site bindings for the websites you host in IIS.