After deploying the CCA you find that specific machines only ever receive HTTP 401 responses from the Management Server. The agent's registry entries under HKLM\Software\AppSense Technologies\Communications Agent\ show the correct server address and ports and you can reach the Management Server through a browser by going to one or more of these addresses (depending on your configuration):
http://<management server hostname>/managementserver/deployment/manifest.aspx
http://<management server hostname>:7751/managementserver/deployment/manifest.aspx
https://<management server hostname>:443/managementserver/deployment/manifest.aspx
http://<management server vip>/managementserver/deployment/manifest.aspx
https://<management server vip>:443/managementserver/deployment/manifest.aspx
When looking at the AppSense event logs in Windows Event Viewer you can see events describing HTTP 401 responses. Inspecting the IIS logs on the Management Server (by default in c:\inetpub\logs\<IIS instance>\) shows the same. For a working client you instead see an initial 401 response followed by a 200 indicating success.
Solution / Workaround
This issue has been seen to be caused by a bad cached credential in the Windows Credential Vault. You can check this by opening Control Panel\User Accounts\Credential Manager and verifying that there is no entry for the Access Credentials specified in the Global Settings in the Management Server console. This credentials should not be cached and using this view you can remove it. Restart the CCA afterwards which should now register without issue.