GroupManager Help!

Could someone please help me out a bit setting up a new server and trying out Group manager,I tried everything i could but still nothing basically what i need to do is say someones in Group Moderator i need his name to be [Mod]Test but everytime i a try to do it , it just goes TestMod for some reason

Owner:
default: false
permissions:
- '*'
- -vanish.*
inheritance:
- admin
info:
prefix: '&4'
build: true
suffix: '&2[Owner]'