diff --git a/xmpp-vala/src/core/direct_tls_xmpp_stream.vala b/xmpp-vala/src/core/direct_tls_xmpp_stream.vala
index ee796350..8819e2df 100644
--- a/xmpp-vala/src/core/direct_tls_xmpp_stream.vala
+++ b/xmpp-vala/src/core/direct_tls_xmpp_stream.vala
@@ -1,6 +1,6 @@
 public class Xmpp.DirectTlsXmppStream : TlsXmppStream {
 
-    const string[] ADVERTISED_PROTOCOLS = {"xmpp-client"};
+    const string[] ADVERTISED_PROTOCOLS = {"xmpp-client", null};
 
     string host;
     uint16 port;