What should I check if one floodlight is out on a mast?

If only one floodlight is out on a mast what should I check?

1. Check that all the cables of that floodlight are securely connected
2. Check that all connectors are plugged in correctly and plugs are tight/secure
3. check that connectors have no water ingress
4. Check to make sure SPD (surge protection devices) are installed