Can someone please help me with PEX?

Hello, it's Fludude.
I require some help with PEX. I seem to have all the permissions functioning correctly no problem, but I can't get any prefixes to work at all.

The plugins I am using are:
PEX
ChatManager
Buycraft
NoCheatPlus
CompactNoCheatPlus
Essentials
EssentialsSpawn
Factions
FastSoup
FirstJoinPlus
LinksOnSigns
mcmmo
PersonalMOTD
ScheduledAnnouncer
Votifier
Worldedit

My pex file is as follows.

users:
Fludude:
group:
- OwnerFludude
jakecolman1:
group:
- OwnerJake
groups:
Member:
default: true
permissions:
- modifyworld.*
- fastsoup.use
- essentials.spawn
- essentials.rules
- essentials.motd
- essentials.list
- essentials.helpop
- essentials.help
- essentials.afk
- essentials.balance
- essentials.balancetop
- essentials.home
- essentials.kit
- essentials.kit.starter
- essentials.me
- essentials.msg
- essentials.pay
- essentials.sethome
- essentials.signs.use.*
- essentials.suicide
- essentials.tpa
- essentials.tpaccept
- essentials.tpahere
- essentials.tpdeny
- essentials.warp
- essentials.warp.list
- essentials.ban.notify
- essentials.kick.notify
- essentials.ptime
options:
build: true
rank: '1000'
Moderator:
permissions:
- essentials.broadcast
- essentials.jails
- essentials.kick
- essentials.mute
- essentials.time
- essentials.time.set
- essentials.ptime
- essentials.ptime.others
- essentials.togglejail
- essentials.tp
- essentials.unban
- essentials.weather
- vanish.list
- vanish.vanish
- vanish.see
inheritance:
- Member
options:
build: true
rank: '500'
Admin:
permissions:
- essentials.ban
- essentials.unban
inheritance:
- Moderator
options:
build: true
rank: '500'
OwnerFludude:
permissions:
- '*'
inheritance:
- Admin
options:
build: true
rank: '250'
prefix: '&b[Owner]&b'
OwnerJake:
permissions:
- '*'
inheritance:
- Admin
options:
build: true
rank: '125'


I'd be very grateful if someone could help me.

Thanks,
Fludude.