Users complain that all printers mapped from the Citrix Universal Print Server are in an offline state. What could be the likely cause of this issue?

Setting the Universal Print Server policy to 'Disabled' would cause printers to fall back to native Windows printing or become unavailable, not specifically render them offline.

The Citrix Universal Print Service is the Windows service installed on the Universal Print Server that brokers print jobs and maintains printer state for connected VDA sessions. When this service stops, the VDAs can no longer communicate with the print server over the UPS protocol, causing every mapped Universal Print Server printer to report an offline state. Restarting this service on the print server resolves the issue immediately without any policy or configuration changes.

Stopping the Windows Print Spooler on the VDA/Server OS machines would affect local spooling on those machines, but the offline status of UPS printers originates from the print server side, not the VDA side.

The 'Enabled with no fallback to Windows native' policy setting controls fallback behavior when UPS is unreachable but does not by itself cause printers to go offline.