Wake on lan

The socket connection could not be established. exception 'SocketConnectionException' with message 'Could not open socket to udp://skjold78.duckdns.org on port 2001. Error: php_network_getaddresses: getaddrinfo failed: No such host is known. ' in C:\home\site\wwwroot\wake\wake_on_lan.php:141 Stack trace: #0 C:\home\site\wwwroot\wake\wake.php(21): WakeOnLAN('1C-87-2C-61-1E-...', 'skjold78.duckdn...') #1 {main}