Technical Tip: How to register license or solve expired license error

[Pedro_FTNT]

Description
This article describes how to register license or solve expired license error after changing FortiGate or ISP Internet Connection error.
Scope
All FortiOS Versions
Solution
In order to test the connection to FortiGuard:

1) Check FortiGate DNS servers:

    Go to System / DNS / Configure the DNS: 

    208.91.112.53 
    208.91.112.52 

2) Run diagnose and sniffers commands as follows:

di de app update -1 
di de enable 
exe update-now

3) Check License Registration