Problem/Bug PremissionEx not working

So i was creating my new server when i made my permissions list in Permissions ex plugin. My server is on 1.12
Spigot.When i first added some things to permissions.yml file in the Permisions Ex folder it worked but then when i completed my permissions file it didn't work. When I type /pl ingame only the PermissionsEx is in red.Here's the permissions file :

Code:

groups:
  Default:
    default: true
    build: true
    prefix: '&7[&2Member&7]&8=>&7'
    suffix: '&8'
    permissions:
    - chatex.allowchat
    - essentials.help
    - modifyworld.chat
    - modifyworld.*
    - essentials.home
    - essentials.sethome
    - essentials.back
    - essentials.tpa
    - essentials.tpaccept
    - essentials.tpdeny
    - essentials.spawn
  Youtuber:
    build: true
    inheritance:
    - Default
    prefix: '&7[&cYoutuber&7]&8=>&4'
    suffix: '&c'
    permissions:
    - essentials.colorchat
    - essentials.enchant
    - essentials.repair
    - essentials.vanish

  Moderator:
    build: true
    inheritance:
    - Default
    - Youtuber
    prefix: '&8[&6Moderator&8]&7=>&3'
    suffix: '&6'
    permissions:
    - essentials.kill
    - essentials.kill.*
    - essentials.heal
    - essentials.item
    - essentials.give
    - essentials.fly
    - essentials.kick
    - essentials.mute
    - essentials.tjail
    - essentials.jail
    - essentials.tempban
    - essentials.vanish
  Admin:
    build: true
    inheritance:
    - Default
    - Moderator
    - Youtuber
    prefix: '&8[&9Admin&8]&7=>&3'
    suffix: '&9'
    permissions:
    - worldedit.*
    - essentials.gamemode
    - essentials.ban
    - essentials.unban
    - essentials.ipban
    - essentials.unipban
    - essentials.pardon
    - essentials.enchant
  Owner:
    build:true
    inheritance:
    - Admin
    prefix: '&9[&4Owner&9]&0=>&5'
    suffix: '&b'
    permissions:
    - '*'