Agents of specific computers are suddenly unable to download packages. The agent logs and also the log.xml file in the Software Delivery sub folder, where the individual package information is stored, contains the following warning or error:
No package sources returned by server (-2147023728)
The affected computers exist in a subnet which is assigned to a Site, and that site is assigned to a Package Server that does not exist, is not responding, or is having difficulty downloading packages directly from the Notification Server itself.
Notification Server 6.0.6074