Addendum to
https://techdocs.broadcom.com/us/en/ca-enterprise-software/it-operations-management/application-performance-management/20-2/troubleshooting/agent-troubleshooting/Agent-Starts-but-Not-Visible.html
Application Performance Management 10.7/20.2
It describes a scenario using 20.2 agent with 10.7 Enterprise Manager
When the agent is downloaded it will automatically have the ws protocol in the connection string
agentManager.url.1=ws://<APM services gateway URL>
This denotes a websocket communication which is how 20.2 agent connects to DX APM 20.2 server
For use with APM 10.7 Enterprise Manager, it is necessary to remove the ws:// at the front,
This is effectively the same connection string as when using a 10.7 agent.
The agent will then use the tcp protocol for direct socket communication.
agentManager.url.1=<EM host>:5001