After upgrading to FortiOS 7.6.8, GUI HTTPS stops working

Description

Upgrading a FortiGate device to version 7.6.8 may cause the web administration interface to become unavailable, resulting in the firewall sending TCP resets to HTTPS requests.

Scope

FortiGate 7.6.6 and above.

Solution

Root cause

If the FortiGate belongs to the security fabric, the root is running 7.4.x, and the leaf FortiGate version is 7.6.8: the stability of the web administration service will be affected and application crash autod will be generated.

Resolution

Upgrade the FortiGate root to the same version of the leaf FortiGate, or apply the following workaround:

config automation setting
    set fabric-sync disable
end

Troubleshooting the web interface

If the web interface does not respond, verify the current management port settings using the following command:

get system global | grep -E "admin-sport|management-port"

Run the https and http_auth daemons commands. If no information is shown, review whether the TCP port for the admin port is open, and whether the gnum 10000e and 10000f policies show the https is open to the interface the packet is entering through.