Unable to access Web GUI after upgrade from 7.2.3 to 7.2.7 (100F)

[aitee]

I just upgraded my FG 100F from 7.2.3 to 7.2.7 using the recommended upgrade path (7.2.3 - 7.2.5 - 7.2.7). After upgrade, all FAP 221e stopped working. Wireless network is down. Wired network works though.

So with the upgrade, I am now unable to access the web gui. I can only access it thru ssh. I was not able to troubleshoot why my wireless network is down so I downgraded back to 7.2.3 then restored the backup. After restore, wireless is now back and working.

But web gui access is still "refused to connect". Prior to upgrade, I am able to access it with https://ipv4:8443.

I tried all troubleshooting guides I found but I can't get it to work.

Here's some that might help:

config system global
    set admin-sport 8443
    set admintimeout 10
    set alias "FortiGate-100F"
    set auth-cert "Fortinet_GUI_Server"
    set autorun-log-fsck enable
    set gui-certificates enable
    set gui-fortigate-cloud-sandbox enable
    set gui-theme onyx
    set gui-wireless-opensecurity enable
    set hostname "HMHO"
    set management-port-use-admin-sport disable
    set switch-controller enable
    set timezone 38
end

config system interface
    edit "lan"
        set vdom "root"
        set ip 192.168.0.1 255.255.255.0
        set allowaccess ping https ssh snmp http fgfm fabric
        set type hard-switch
        set alias "LAN"
        set stp enable
        set device-identification enable
        set role lan
        set snmp-index 11
        config ipv6
            set ip6-address ::ffff:192.168.0.1/128
        end
    next
end

[srajeswaran]

Can you make sure admin-server-cert is configured as below and check?

# config sys global
     set admin-server-cert Fortinet_Factory
end

if this is already configured, please try the debugs mentioned in below article.
https://community.fortinet.com/t5/FortiGate/Technical-Tip-GUI-is-not-reachable-after-upgrade/ta-p/19...

[AEK]

Regarding FAP outage, try upgrade your FAP to 7.2.3.

Ref: https://docs.fortinet.com/document/fortiap/7.4.0/fortiap-and-fortios-compatibility-matrix/209640/for...

In case the issue persists, you may try set the below to allow backward compatible ciphers.

config wireless-controller global
  set tunnel-mode compatible
end