FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
Article Id 277938
Description This article describes how to fix the issue when the FortiGate GUI is not loading after the upgrade to v7.2.5.
Scope FortiGate v7.2.5 and onwards.
  1. Make sure to use the correct admin-sport.


For example, the settings shown below use port 8443.


config system global

    set admin-sport 8443

end or https://<Ipaddress>:8443 should be used.



  1. Check if the admin-server-cert settings have the right certificate with hash above SHA-1 (which is not supported anymore).


Starting in FortiOS v7.2.5, users should use the built-in Fortinet_Factory  certificate, or SHA-256 and higher certificates for the web management interface.


For example: 


config system global 

    set admin-server-cert Fortinet_Factory 



SHA1 would not be supported anymore from v7.2.5 onwards.

Related document:
Remove support for SHA-1 certificate used for web management interface (GUI)