Resolve Fortinet Error: Unable to connect to Fortiguard servers

If your Fortinet firewall has suddenly begun displaying a "Unable to connect to Fortiguard Servers" message, here's the fix:


Login to Fortigate with administrator account
Launch CLI


config system fortiguard
    set fortiguard-anycast disable
    set protocol https
    set port 443
end

execute update-now


Give the system a few minutes and the error should resolve.

Fortinet also provides this alternative:

config system fortiguard
set fortiguard-anycast disable
set protocol udp
set port 8888
set sdns-server-ip 208.91.112.220 173.243.140.53 210.7.96.53 200.91.112.220
end

execute update-now

# FortiGate Real-Time Debug Commands for FortiGuard Troubleshooting

## 1. FortiGuard License & Package Updates Debug
# Use this to troubleshoot firmware updates, AV definitions, or IPS signatures.
diagnose debug reset
diagnose debug application updateff -1
diagnose debug enable

# Trigger the update check manually in a separate window or after enabling debug:
execute update-now


## 2. Web Filtering & Rating Lookups Debug
# Use this to troubleshoot web filtering rating timeouts and certificate validation.
diagnose debug reset
diagnose debug application urlfilter -1
diagnose debug enable

# Test the rating resolution manually from the CLI:
diagnose fortiguard url-rating get google[.]com
*note: remove the [ ] when issuing the command. They're added to prevent LI from automatically creating a URL link.

## 3. Active FortiGuard Server List Matrix
# Use this to verify that the firewall has successfully switched to unicast nodes.
diagnose fortiguard table


## 4. Turn Off Debug Logging
# Run this immediately after capturing data to prevent high CPU utilization.
diagnose debug disable
diagnose debug reset