http://pastebin.com/P8THhcpd
I'm have the group Fonda: but with this config I have the standard chat. And for essentialschat my group is default, not Fonda (when a write in chat)

I have latest Spigot 1.8.8, in BungeeCord Network.
I use GroupManager for groups & permissions.

There is dependencies with Vault. I didn't have Vault, the reason why essentialschat doesn't work.