FortiOS 7.4.11 unexpected issues

Forum|Forum|13 days ago
September 2, 2026
3 replies
201 views

Hello everyone! Recently we upgraded our Fortigate (120G HA Active-Passive cluster) from 7.2.11 to 7.4.11, and different problems started to occur.

Some users spontaneously lose access to the Internet with ERR_TUNNEL_CONNECTION_FAILED (we use explicit proxy with Kerberos authentication and deep ssl inspection). It happens at random times and with random users, lasts usually up to 2-3 minutes, then works as usual.

FortiGates started to randomly reboot with the message "Fortigate had experienced an unexpected power off!", there's no CPU/RAM issue, usually mem is around 40%, and proc is around 10-12%. Due to fast HA failover users don't feel the interruption, but it's definitely not a good sign. Before the update both NGFW had worked for 367 days.

Anyone experienced similar issues? Any workarounds? Or should I just be rolling back to 7.2.11?

Any advice and help will be appreciated. Thank you in advance!

xshkurti

Staff

@ragnar21

Try to apply this workaround:

config ips global
set np-accel-mode none
end

Monitor for a couple of days and let us know the results so that others with the same issue can find this as a solution.

It seems to be related to some kernel panic so if the above change does not help, then kernel panic logs need to be captured via a console connection to the device and report it to TAC team.
Troubleshooting Tip: How to deal with a Kernel panic | Community

-X-

S

s1k0_s3ba

Visitor III

i would not roll back immediately. since the problems started right after upgrading to 7.4.11, i would first collect some evidence and check the known issues.

there is a 7.4.11 known issue, bug 1256278, where packet loss can occur on soc5 models with ingress shaping and asic offload enabled. fortinet staff confirmed it was initially reported on a 120g, and it is fixed in 7.4.12.

https://community.fortinet.com/support-forum-92/need-explanation-for-bug-id-1256278-228129

https://docs.fortinet.com/document/fortigate/7.4.11/fortios-release-notes/236526/known-issues

7.4.12 also includes several fixes related to explicit proxy and wad, so i would consider testing 7.4.12 before going back to 7.2.11.

https://docs.fortinet.com/document/fortigate/7.4.12/fortios-release-notes/289806

for the random reboots, i would check:

get system status | grep -i reason

diagnose debug crashlog read

the “unexpected power off” message can also appear after an unexpected reboot/kernel panic, not only after an actual power loss.

https://community.fortinet.com/fortigate-3/technical-guide-identifying-the-fortigate-reboot-reasons-and-what-to-do-next-209310

since both units were stable before the upgrade, i would collect the crashlog and open a tac case before deciding between 7.4.12 and rollback.

S