Thank you for posting your question. Are you using a distribution server with your agents or are they getting their data from vendor over internet?
If you are using a distribution server, then you need to make sure that the distribution server assigned in your agent policy is actually having data synced to it in Tools > Operations > Distribution Server. The agents would be retrieving the data from the distribution server and not the console.
If you are using Vendor over Internet then you would need to check to make sure that your firewall is not blocking the manifest.
Sorry for the slow reply. I start work at 4am so by the time your response came in I was buttoning things up for the day.
Currently we are going to the Internet. Probably go with the console server being the Distribution server in the near future instead, but for now Internet is what we are using. I don’t think it is a firewall issue as a lot of the PCs are having no problem communicating to the console, or getting updates. They all use the same proxy, same proxy credentials and same firewall rules. I found yesterday that if I removed the machine from the console, uninstalled the agent from the PC, cleaned the registry of all LandDesk/Shavlik entries, rebooted then reinstalled the agent locally, at least one PC regained communication and is now showing updates and patches missing. Some PCs did not succeed, even after doing all those steps. So some progress but unsure why 21 machine out of 80 or so did not seem to install properly. Still a mystery in progress.
Thanks for the input.