If you come across an issue were you are unable to power on a VM on vCenter 6.
Error Received : A general System error occurred. No connection could be made because the target machine actively refused it.
This can happen if you accidentally stopped the VMware vCenter workflow manager service.
Start the VMware vCenter workflow manager service and vm power on operations works fine.
I believe this is the orchestrator workflow service , but the integration of it related to powering on vm is interesting.
I believe we need to wait and check on more information from VMware.
Happy Thinking 🙂