shadowsocks/shadowsocks-windows · error · ArgumentException

No server configured

Error message

No server configured

What it means

Thrown as ArgumentException from TCPRelay.CreateRemote when GetAServer returns null or a server whose `server` field is empty, meaning no usable upstream Shadowsocks server is available for the connection. This is a configuration/availability failure: the strategy and server list could not select a target. It fires before the encryptor is created.

Source

Thrown at shadowsocks-csharp/Controller/Service/TCPRelay.cs:264

        // TODO: decouple controller
        public TCPHandler(ShadowsocksController controller, Configuration config, Socket socket)
        {
            _controller = controller;
            _config = config.proxy;
            _connection = socket;
            _proxyTimeout = config.proxy.proxyTimeout * 1000;
            _serverTimeout = config.GetCurrentServer().timeout * 1000;

            lastActivity = DateTime.Now;
        }

        public void CreateRemote()
        {
            Server server = _controller.GetAServer(IStrategyCallerType.TCP, (IPEndPoint)_connection.RemoteEndPoint,
                _destEndPoint);
            if (server == null || server.server == "")
            {
                throw new ArgumentException("No server configured");
            }

            _encryptor = EncryptorFactory.GetEncryptor(server.method, server.password);

            _server = server;

            /* prepare address buffer length for AEAD */
            Logger.Trace($"_addrBufLength={_addrBufLength}");
            _encryptor.AddrBufLength = _addrBufLength;
        }

        public void Start(byte[] firstPacket, int length)
        {
            _firstPacket = firstPacket;
            _firstPacketLength = length;
            HandshakeReceive();
        }

View on GitHub (pinned to 891d971682)

Solutions

1. Add at least one valid server in the configuration (address, port, method, password).
2. If using a strategy, check that it has not disabled all servers; switch to a simpler strategy or reset server reachability.
3. Validate gui-config.json for any server entries with an empty `server` field and fix or remove them.
4. Ensure GetAServer's caller/endpoint logic can actually select from the configured list.

Example fix

// before
Server server = _controller.GetAServer(IStrategyCallerType.TCP, (IPEndPoint)_connection.RemoteEndPoint, _destEndPoint);
if (server == null || server.server == "")
    throw new ArgumentException("No server configured");

// after: keep the connection open with a clearer message and a guard upstream
if (server == null || string.IsNullOrWhiteSpace(server.server))
    throw new ArgumentException("No server configured (add a server or check HA strategy state)");

// Ensure a usable server exists before relaying
if (_controller.GetCurrentServer() is null || string.IsNullOrWhiteSpace(_controller.GetCurrentServer()?.server))
    return; // drop the connection cleanly instead of throwing

bool HasUsableServer(Configuration c) =>
    c.configs != null && c.configs.Any(s => !string.IsNullOrWhiteSpace(s?.server));

try { relay.CreateRemote(); }
catch (ArgumentException ex) when (ex.Message == "No server configured")
{ /* close the connection, notify UI to add a server */ }

When it happens

Trigger: The server list is empty or every server was filtered out by the active strategy (e.g. all marked unreachable by a high-availability strategy); the selected server has a blank address field due to a malformed config; GetAServer returned null because no server matched the caller/endpoint criteria.

Common situations: Fresh install with no servers added; user deleted all servers; HA strategy disabled all servers after repeated failures; a manually edited gui-config.json left a server with an empty address.

Related errors

• Server IP can not be blank
• {callbackName} not found
• Unknown forward proxy.
• method not found
• failed to set key

AI-assisted analysis of shadowsocks/shadowsocks-windows@891d971682 (2026-08-13). Data as JSON: /api/errors/3096a3dac78cd2e2. Report an issue: GitHub.