This error usually appears when Event Log Manager is configured to collect event logs without agent services (i.e. network traffic compression option is turned off).
Generally there are few reasons why this error appears:
The problematic server is turned off or not accessible through the network.
The "Server" service is stopped on the problematic server.
The "File & Printer Sharing for Microsoft Networks" feature is turned off in the Local Area Connection properties.
The remote connection is blocked by "Windows Firewall".