If the FortiGates do not form a cluster, try the following:
- Connect to each cluster unit's GUI and verify that the HA configurations are the same. The HA configurations of all cluster units must be identical – even a small discrepancy can prevent a FortiGate from joining a cluster.
- If the configurations are the same, try re-entering the HA password on each cluster unit in case you made an error typing the password when configuring one of the cluster units.
- Check the cables and interface LEDs.
- Check that the correct interfaces of each cluster unit are connected. Use the cluster members list to verify that each interface that should be connected actually is connected. If a link is down, re-verify the physical connection.
- Try replacing network cables or switches.