Nickname login, skins, and authentication

By default, the server verifies the Minecraft license. A player connecting from a client with an offline account gets “Failed to verify username” / Failed to verify username.

Allow nickname login

Go to “Settings” → “Nickname login”. That's all — no need to edit any files.

There's a third option as well — “Sign in only with a Millida account”: the nickname is confirmed by your account on the platform rather than by the launcher. It's a handy compromise if you don't run your own registration system on the server.

What breaks along with the license

Without verification, a nickname is just a string the player typed in themselves. This has three inevitable consequences.

1. You need an authentication plugin. AuthMe or nLogin: the player registers with a password (/register password password) and logs in with the same one (/login password). Without it, the first person to come along will grab your admin nickname. Install it from the catalog in the “Plugins and mods” section.

2. Skins disappear. A client with an offline account can't pull a skin from Mojang's servers. The fix is the SkinsRestorer plugin: it fetches skins by nickname or by link, and the player command is /skin name.

3. The whitelist stops being protection — see Whitelist.

It also makes sense to install an anti-bot plugin if the server is public: servers with nickname login attract bots in droves.

Progress when you switch modes

This is the main trap. Inventories, homes, claims and balances are tied to a UUID, and the same nickname has a different UUID in licensed mode and in nickname-login mode. Switch it, and players log in as “new” players with empty hands.

What to do:

• Decide on the mode before you launch the project, not after the first month of play.
• If you do have to switch, make a copy of the world in “World and copies” in advance.
• Items and homes are transferred manually: inventories with commands via “Players and access”, claims and balances by reassigning them to the new UUID in the plugin.
• With plugins that support it (for example, Essentials), it's easier to move the player file <old-uuid>.yml to <new-uuid>.yml through the Files section — with the server stopped.

You can't preserve progress “with one button” when switching modes on any hosting: a different UUID is literally a different player as far as the server is concerned.

Server network

When you use a proxy, the proxy performs the license check, and the backends trust it. See how we set this up — Server network and your own proxy.