                 Log.error("Error listening on port \(port): \(error). Use server.failed(callback:) to handle")
             }
         }
+        serverLock.unlock()
     }
 
     // MARK: Stop Servers

    ///
    /// - Parameter unregister: If servers should be unregistered after they are stopped (default true).
    public class func stop(unregister: Bool = true) {
        for (server, port) in httpServersAndPorts {
            Log.verbose("Stopping HTTP Server on port \(port)...")
            server.stop()

        let server = FastCGI.createServer()
        server.delegate = delegate
        server.allowPortReuse = allowPortReuse
        serverLock.lock()
        fastCGIServersAndPorts.append((server: server, port: port))
        serverLock.unlock()
        return server
    }

