Technical TIP : Local FDS update may fail when devices are hidden in FortiManager

[kishizuka_FTNT]

Description	This article describes technical guidance for scenarios where FortiManager is used solely as a Local FDS (FortiGuard Distribution Server) without registering FortiGate devices. If a device is hidden in Device Manager, update operations may fail. This behavior occurs because FortiGate devices that are hidden in the FortiManager device list are not eligible for Local FDS updates.
Scope	Product: FortiGate, FortiManager. Feature: Local FDS. Versions: All supported versions.
Solution	FortiManager allows the use of the Local FDS feature without registering FortiGate devices. In this mode, unregistered devices appear in the Device Manager as Unregistered devices. These devices can be hidden from the list using the Hide button.   However, once a device is hidden, it will be treated as a Hidden device, and hidden devices are not allowed to use the Local FDS service. As a result, when the FortiGate attempts to perform an update through Local FDS, the operation fails with a 401 response. FortiGate debug log example: diagnose debug application update -1 diagnose debug enable execute update-now ... get_fcpr_response[298]-Response=401|Persistent=false upd_pkg_verify_update_rsp[1124]-Unexpected update rsp code 401 FortiManager debug log example: diagnose fmupdate view-linkd-log fds info fds_svrd: __check_unreg_device: device FGVM02TM25000841 is hidden, skip update warn fds_svrd: check unreg failed for FGVM02TM25000841 info fds_svrd: Response=401|Persistent=false Recovery step from the Hidden devices: Delete the hidden device entry in FortiManager. The device can be made visible again by selecting 'Display Hidden Devices'. After reappearing, the device can be deleted from the device list. Once deleted, the FortiGate will appear as an Unregistered device instead of a Hidden device when attempting the next update. After this process, the FortiGate can successfully perform updates via the Local FDS.