You may have problems collecting metrics after an upgrade or install of vROPS for Horizon in later versions of 6.x.
Check the v4v-agent log on you virtual desktop. Located in %PROGRAMDATA%\VMware\VDM\logs\v4v-agent-date.log. If you see error logs:
ERROR Failed to send startup message to the message server. java.rmi.ConnectIOException: error during JRMP connection establishment; nested exception is:
javax.net.ssl.SSLHandshakeException: Received fatal alert: handshake_failure
This has caught me at out when running newer versions of vROPS (6.2.1 and 6.3) in environments with older versions of view, in this case 6.0.1. The reason being that the old version of the view agent used TLS 1.0 and the latest versions of vROPS and View are only configured to use TLS 1.2 as default.
To fix the issue:
Login with root via the console or SSH to your vROPS for horizon collector and edit /usr/lib/vmware-vcops/user/plugins/inbound/V4V_adapter3/work/msgserver.properties file using vi editor.
Add the following line.
enforcesslprotocols = false
Save the file and restart the Horizon Adapter.
If you are still not receiving metrics then rerun the Horizon Broker and Horizon Adapter pairing on the connection server.