Technical Tip: "403 Forbidden error" or "500 Internal sever error" while accessing management GUI

Description

This article describes about two common issues faced while accessing management GUI.

1. '403 Forbidden error' 
2. '500 Internal server error'

Scope

FortiAuthenticator.

Solution

For Error 1:
Post login to FortiAuthenticator, if the below error appears then make the suggested changes and test the access.
'403 Forbidden You are not allowed to access this resource.' Contact the administrator.

• Ensure to verify if the resources for the dedicated port are defined.
• Access the unit using SSH or console.
• Edit the interface and enable 'gui' option in allowaccess.

Example (Older version):

config system interface

    edit port1
        set allowaccess ssh https GUI
    next
end 

In newer OS versions:

config system interface
    edit port1
     set allowaccess ?

snmp|ssh|telnet|http-gui|https-api|https-fabric|https-gui
e.g. allowaccess ssh https-gui

Note that if HTTP needs to be enabled, the command will be as:

set allowaccess ssh https-gui http-gui ssh 

For Error 2 :

If the issue appears always or randomly, ensure to check the VM requirements.

Refer to the article  Reasons and Solutions of FortiAuthenticator 500 Internal server error

If the issue persists after the post above solutions, open a TAC case with specified logs on the article link above.