diff --git a/libdino/src/service/calls.vala b/libdino/src/service/calls.vala
index 4c3bbea7..365c15d9 100644
--- a/libdino/src/service/calls.vala
+++ b/libdino/src/service/calls.vala
@@ -124,11 +124,15 @@ namespace Dino {
             XmppStream? stream = stream_interactor.get_stream(account);
             if (stream == null) return;
 
-            Xep.Jingle.Session session = yield stream.get_module(Xep.JingleRtp.Module.IDENTITY).start_call(stream, full_jid, video, sid);
-            sessions[call] = session;
-            sid_by_call[call.account][call] = session.sid;
+            try {
+                Xep.Jingle.Session session = yield stream.get_module(Xep.JingleRtp.Module.IDENTITY).start_call(stream, full_jid, video, sid);
+                sessions[call] = session;
+                sid_by_call[call.account][call] = session.sid;
 
-            connect_session_signals(call, session);
+                connect_session_signals(call, session);
+            } catch (Error e) {
+                warning("Failed to start call: %s", e.message);
+            }
         }
 
         public void end_call(Conversation conversation, Call call) {
diff --git a/plugins/rtp/src/module.vala b/plugins/rtp/src/module.vala
index 0edbb3e1..dfe224aa 100644
--- a/plugins/rtp/src/module.vala
+++ b/plugins/rtp/src/module.vala
@@ -20,7 +20,7 @@ public class Dino.Plugins.Rtp.Module : JingleRtp.Module {
         string pipeline_desc = @"$(media)testsrc is-live=true ! $element_desc ! appsink name=output";
         try {
             var pipeline = Gst.parse_launch(pipeline_desc);
-            var output = (pipeline as Gst.Bin).get_by_name("output") as Gst.App.Sink;
+            var output = ((Gst.Bin) pipeline).get_by_name("output") as Gst.App.Sink;
             SourceFunc callback = pipeline_works.callback;
             var finished = false;
             output.emit_signals = true;
diff --git a/xmpp-vala/src/core/direct_tls_xmpp_stream.vala b/xmpp-vala/src/core/direct_tls_xmpp_stream.vala
index 43b7114a..ee796350 100644
--- a/xmpp-vala/src/core/direct_tls_xmpp_stream.vala
+++ b/xmpp-vala/src/core/direct_tls_xmpp_stream.vala
@@ -1,5 +1,7 @@
 public class Xmpp.DirectTlsXmppStream : TlsXmppStream {
 
+    const string[] ADVERTISED_PROTOCOLS = {"xmpp-client"};
+
     string host;
     uint16 port;
     TlsXmppStream.OnInvalidCertWrapper on_invalid_cert;
@@ -18,7 +20,7 @@ public class Xmpp.DirectTlsXmppStream : TlsXmppStream {
             IOStream? io_stream = yield client.connect_to_host_async(host, port);
             TlsConnection tls_connection = TlsClientConnection.new(io_stream, new NetworkAddress(remote_name.to_string(), port));
 #if ALPN_SUPPORT
-            tls_connection.set_advertised_protocols(new string[]{"xmpp-client"});
+            tls_connection.set_advertised_protocols(ADVERTISED_PROTOCOLS);
 #endif
             tls_connection.accept_certificate.connect(on_invalid_certificate);
             tls_connection.accept_certificate.connect((cert, flags) => on_invalid_cert.func(cert, flags));
diff --git a/xmpp-vala/src/module/xep/0045_muc/module.vala b/xmpp-vala/src/module/xep/0045_muc/module.vala
index 21c7b2a0..718ad255 100644
--- a/xmpp-vala/src/module/xep/0045_muc/module.vala
+++ b/xmpp-vala/src/module/xep/0045_muc/module.vala
@@ -9,7 +9,6 @@ private const string NS_URI_USER = NS_URI + "#user";
 private const string NS_URI_REQUEST = NS_URI + "#request";
 
 public enum MucEnterError {
-    NONE,
     PASSWORD_REQUIRED,
     BANNED,
     ROOM_DOESNT_EXIST,
@@ -286,7 +285,7 @@ public class Module : XmppStreamModule {
             Jid bare_jid = presence.from.bare_jid;
             ErrorStanza? error_stanza = presence.get_error();
             if (flag.get_enter_id(bare_jid) == presence.id) {
-                MucEnterError error = MucEnterError.NONE;
+                MucEnterError? error = null;
                 switch (error_stanza.condition) {
                     case ErrorStanza.CONDITION_NOT_AUTHORIZED:
                         if (ErrorStanza.TYPE_AUTH == error_stanza.type_) error = MucEnterError.PASSWORD_REQUIRED;
@@ -313,7 +312,7 @@ public class Module : XmppStreamModule {
                         if (ErrorStanza.TYPE_CANCEL == error_stanza.type_) error = MucEnterError.USE_RESERVED_ROOMNICK;
                         break;
                 }
-                if (error != MucEnterError.NONE) {
+                if (error != null) {
                     flag.enter_futures[bare_jid].set_value(new JoinResult() {muc_error=error});
                 } else {
                     flag.enter_futures[bare_jid].set_value(new JoinResult() {stanza_error=error_stanza.condition});