Hi Rosse. It seems this fgt is running a special firmware build (See also KB FD33316), such that it may not be " fully compatible" with modern browser versions. If the fgt device has been online (without a reboot) for 60+ days, I suggest try rebooting it then see if you can access the GUI. (You could try installing an older version of firefox...but is not recommend.) If you can upgrade the firmware on the fgt, I suggest doing that (though you may need to contact fortinet support to confirm which firmware you can load on it).
NSE4/FMG-VM64/FortiAnalyzer-VM/6.0 (FWF30E/FW92D/FGT200D/FGT101E/FGT81E)/ FAP220B/221C
Fortigate <3
The Fortinet Security Fabric brings together the concepts of convergence and consolidation to provide comprehensive cybersecurity protection for all users, devices, and applications and across all network edges.
Copyright 2024 Fortinet, Inc. All Rights Reserved.