The CLI tool will need to be present on the device for that command to work. I believe if you use Connectwise to deploy SEPC it should be present. This video is the best demonstration of how to do this that I'm aware of: https://help.symantec.com/cs/PMC_SEPC/PMC_SEPC/v127236586_v123881503/Video:-Setting-up-ConnectWise-Automate-to-use-Symantec-Endpoint-Protection-Cloud/?locale=EN_US
As far as the rest of you comment? Unknown and unknowable? I think not.
Let me preface this by saying that this is a manifestation of an issue that is extremely common to SEP SBE cloud, and extremely rare in SEPC.
You got an error message on the agent showing that there was a device license issue correct? And the protection was disabled? https://www.symantec.com/docs/TECH237152
At its heart, this is the same issue as https://www.symantec.com/docs/TECH218313 for SEP SBE. This is actually the number one most common support call for SBE in my experience.
The underlying cause is an issue with the license activation with the agent itself (it has little to do with actual license expiration, so that proposed alert rule is unlikely to help either). There are several possible causes for this.
1. The agent is just plain unable to reach the activation servers. This is most often due to a firewall or proxy blocking the connection.
2. The license has recently been renewed or replaced, and the agent failed to remove the old activation information and replace it with the current information. In this case, this is easily corrected by booting into safe mode and removing the license activation folders.
3. The license has been recently replaced or renewed, and the agent grabbed the current license activation information, but failed to remove the old license activation info, resulting in 2 activation folders present.
However, once the license activation issue has been resolved, it stays resolved, so long as the computer stays active.
The most common times you'll run into this issue is immediately after install, or when bringing the computer back online for the first time after a long time offline.
But the point I'd like to stress is, this issue is much more common to SBE than it is to SEPC. SEPC has a much better activation logic, reducing the chances of this issue recurring. This is also made evident by the apparent ease with which you were able to resolve the issue, just rebooting the device instead of the much more time consuming and elaborate fixes we sometimes need to try in SBE (booting into safe mode and removing the activation folder, etc., etc.).
As near as I can tell, this is the sequence of events you experienced.
1. Upgrade to SEPC.
2. Noticed license issues on some devices. This was probably caused by leftover activation information from the SBE agent.
3. Rebooted the devices, thus clearing the old activation information and resolving the issue.
I highly doubt this is an issue you'll often run across.