Hello I am having trouble getting getGroupPrefix to work. Could you tell me what I am doing wrong? I think it has something to do with the return types in the arguments, but I am stumped on this one:

public void chat(PlayerChatEvent e)
{
Player player = e.getPlayer();
e.setFormat(Ranks.chat.getGroupPrefix(player.getWorld(), player.getName()) + "%s - %s");

}

When I run it on my server it does not show the group prefix. And yes my group prefixes are correctly placed in Group Manager.

you may have global prefixes setup and the chat system you're using is world-sensitive where it will only return a world prefix if you try to get it. Generally you pass null for the world in if you need global prefixes. I suggest checking where you are applying the prefixes.