Plugin Help {prefix} wont work

hello

i have the problem that my prefix wont work
i dont now if the problem is by pex, essentials or multiverse-core
View attachment 30889
i tried a lot reinstaled pex and essentials but it keep whenever its installed

sorry for my broken english(i am from belgium)

i hope you find the problem if you need extra information like a config.ylm file
what not matter its just as you download the plugin but just ask it

i found it it was the plugin superlobby thats randomly start using formates
(how to close a thread