How to Fix "Failed to Verify Username" on a Minecraft Server

The server couldn't confirm your account with Mojang. With a paid account, restart the launcher. To let cracked clients in, set online-mode=false and install a login plugin.

Paid accounts

Your launcher session has usually expired. Close the game and launcher, log in again and rejoin. If every player gets the error at once, Mojang's authentication servers are down; wait it out.

Letting cracked clients in

1. Stop the server in the Crunchy.Host panel.
2. In Files, open server.properties and set online-mode=false.
3. Start the server. The log now warns that it's running in offline mode.

Offline mode has side effects:

• UUIDs change, since they're derived from the username. Existing inventories, stats, ops.json and whitelist.json entries stop matching. Switch before players join, not after.
• Skins stop loading unless you add a skins plugin.
• Players may get Missing profile public key.

Behind Velocity or BungeeCord

Only the proxy should authenticate. Keep online mode on at the proxy, set online-mode=false on every backend, and turn on player info forwarding so real UUIDs and skins pass through. Make sure backends can't be reached directly, or anyone can skip the proxy and join under any name.