Conserve mode
a memory-protection state the FortiGate enters at ~88% RAM and leaves at ~82%, during which it stops accepting new proxy-inspected sessions
Enter at ~88% memory use (red), exit at ~82% (green). While in conserve mode the FortiGate protects itself: by default it fails new sessions that would need proxy inspection (the av-failopen setting controls this — pass, off/drop, one-shot, idledrop). Existing sessions continue. diagnose hardware sysinfo memory and diagnose sys top to find the culprit; it's often a memory leak, an oversized proxy workload, or too many concurrent SSL deep-inspection sessions.