I have a gamemode that is kinda survival with a twist, but if they change their name, they will lose everything in their inv + armor, how can I support this? (Its a bungeecord server with 5 other servers) https://gyazo.com/c69999623397fac5c44e4b0b57740934
Do you use any plugins to save the user inventories? If so your plugin is probably saving the inventories by the usernames.
If you out the server in online-mode (in the file server.propeties) the uuid dont lode the inventory of the player
He's using Bungee, so he has to do that in the BungeeCord config.yml, otherwise BungeeCord wouldn't work anymore.
I think that he had the same problem try to see this link https://www.spigotmc.org/threads/uuid-problem-permissions-inventory-the-whole-playerdata.27582/
Well then he can solve it by enabling IP forwarding in his BungeeCord config and by setting bungeecord to true in his spigot.yml