Troubleshooting Tip: Browser error 'Not secure' when accessing FortiGate GUI

[mle2802]

Description	This article describes how to troubleshoot the 'not secure' browser error that appears when accessing the FortiGate GUI.
Scope	FortiGate.
Solution	When accessing FortiGate GUI for management, the error 'not secure' is observed on the browser. When checking the error detail, there is no information about certificate validity or any certificate warning. This happens due to HTTP being used instead of HTTPS for the GUI while the 'Redirect to HTTPS' setting is not enabled under System -> Settings -> Administration Settings. By default, the browser will display this 'not secure' error when using HTTP. To avoid the error, use HTTPS instead or enable the 'Redirect to HTTPS' setting. When using HTTPS, make sure the certificate used for GUI is trusted by the client; otherwise, a certificate warning will be observed. See Technical Tip: Certificate Error in Admin Access - Fortinet Community for more information. Related articles: Technical Tip: Certificate warning while accessing FortiGate  Technical Tip: GUI Untrusted HTTPS server certificate