Hi

I was trying to setup per server prefixes. I did this:
/lp group snul meta addprefix 100 &8(&r&eSnul&r&8)&7 server=harrypotter
I changed the server name in the config to harry potter and /lp user Christophe6 returns that I have the right prefix. But when I use essentialschat and vault, it returns just Member... How can I solve this?

But when I use essentialschat and vault, it returns just Member

Use EssentialsXChat, not essentialschat
The "Member" is a config setting in Essentials - not to do with Luckperms. Check your Essentials config.

I am using essentialsxchat. The permissions do perfectly work for global ranks...

Are you sure your prefixes are being pulled from LP, and not just the Essentials config file?

What is use-vault-server set to in your LP config?