diff --git a/coap-chat/coap.c b/coap-chat/coap.c
index 745ea36912..f2b4729c14 100644
--- a/coap-chat/coap.c
+++ b/coap-chat/coap.c
@@ -40,6 +40,7 @@ static const coap_resource_t _resources[] = {
 static gcoap_listener_t _listener = {
     &_resources[0],
     sizeof(_resources) / sizeof(_resources[0]),
+    NULL,
     NULL
 };