[Ataros]

If you do not use any script FMB triggers would work if name of a trigger and action are the same.

If you have any script working with your mission you have to add a trigger section to it to allow triggers to work. The most simple one is

public override void OnTrigger(int missionNumber, string shortName, bool active)
    {
        base.OnTrigger(missionNumber, shortName, active);        
        AiAction action = GamePlay.gpGetAction(ActorName.Full(missionNumber, shortName));
        if (action != null)
            action.Do();
    }

Your FMB trigger and action must have the same name if you use this script.

Check if both action and trigger are defined correctly (trigger type, airgroup, etc.) and saved in FMB.