I would recommend to start by checking whether ESMC Agent installed on client machine is actually connecting to ESMC. For this purpose please follow troubleshooting part of documentation - especially status.html log present on client machine might be helpful in this case.
In case ESMC Agent will be connecting to ESMC, most probable issue is that is is using different name in ESMC or is located in different group, which prevented ESMC to remove "dead" duplicate that is rendered as unmanaged.
In case AGENT is not connecting to ESMC, it is crucial to resolve connectivity issues as described in referenced documentation.
