Why does multiplayer reject connection with token mismatch?

Server set auth_callback expecting a token; client didn't send. Match peer_authenticating signal handlers on both sides.

Server: set_auth_callback(verify_func). Client: send_auth(peer_id, data). Server's callback returns OK; both sides emit peer_authenticated then peer_connected.

Don't set auth_callback. Default no-auth flow connects immediately. Use auth only for protected sessions.

Fix: Godot Multiplayer Connection Token Mismatch

Quick answer: Server: set_auth_callback. Client: send_auth before peer_connected. Both sides handle peer_authenticating.

Connection drops with auth error. Server expects token; client sends none. Mismatch.

The Fix

# Server
multiplayer.peer_authenticating.connect(func(id):
    # wait for client send_auth, validate
    multiplayer.complete_auth(id)
)

# Client
multiplayer.peer_authenticating.connect(func(id):
    multiplayer.send_auth(id, "mytoken".to_utf8_buffer())
    multiplayer.complete_auth(id)
)

Symmetric handlers + complete_auth on both sides finishes the handshake. peer_connected emits after.

Verifying

Auth token validates; peers connect. Wrong token: peer_authentication_failed signal.

“Symmetric auth. Connect after.”

Related Issues

For buffer overflow, see overflow. For Synchronizer, see sync.

Match auth callbacks. Connect.