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

    /// Kitura.start()
    ///```
    public class func start() {
        for (server, port) in httpServersAndPorts {
            Log.verbose("Starting an HTTP Server on port \(port)...")
            do {

            httpServersAndPorts.removeAll()
            fastCGIServersAndPorts.removeAll()
        }
        serverLock.unlock()
    }

    typealias Port = Int
    private static let serverLock = NSLock()
    internal private(set) static var httpServersAndPorts = [(server: HTTPServer, port: Port)]()
    internal private(set) static var fastCGIServersAndPorts = [(server: FastCGIServer, port: Port)]()
}
