After reboot, connect a PC to (or any internal port). The PC should get an IP in 192.168.1.x/24 (e.g., 192.168.1.2 ). Open a browser to https://192.168.1.99 (default login: admin / blank password or admin / admin ).
If you formatted the flash, follow these steps: fortigate 30d factory reset full
If you can still log into the FortiGate 30D’s web GUI (HTTPS on port 443), use this method for convenience. However, this is a "full" reset—it keeps the firmware image but wipes the config. After reboot, connect a PC to (or any internal port)