diff --git a/src/main/java/eu/siacs/conversations/xmpp/jingle/JingleConnectionManager.java b/src/main/java/eu/siacs/conversations/xmpp/jingle/JingleConnectionManager.java
index 30bcf66a4..99f20f7f9 100644
--- a/src/main/java/eu/siacs/conversations/xmpp/jingle/JingleConnectionManager.java
+++ b/src/main/java/eu/siacs/conversations/xmpp/jingle/JingleConnectionManager.java
@@ -18,7 +18,6 @@ import eu.siacs.conversations.entities.Message;
 import eu.siacs.conversations.entities.Transferable;
 import eu.siacs.conversations.services.AbstractConnectionManager;
 import eu.siacs.conversations.services.XmppConnectionService;
-import eu.siacs.conversations.ui.util.Attachment;
 import eu.siacs.conversations.xml.Element;
 import eu.siacs.conversations.xml.Namespace;
 import eu.siacs.conversations.xmpp.OnIqPacketReceived;
@@ -47,7 +46,11 @@ public class JingleConnectionManager extends AbstractConnectionManager {
     }
 
     public void deliverPacket(final Account account, final JinglePacket packet) {
-        //TODO check that sessionId is not null
+        final String sessionId = packet.getSessionId();
+        if (sessionId == null) {
+            respondWithJingleError(account, packet, "unknown-session", "item-not-found", "cancel");
+            return;
+        }
         final AbstractJingleConnection.Id id = AbstractJingleConnection.Id.of(account, packet);
         final AbstractJingleConnection existingJingleConnection = connections.get(id);
         if (existingJingleConnection != null) {
@@ -78,7 +81,6 @@ public class JingleConnectionManager extends AbstractConnectionManager {
         } else {
             Log.d(Config.LOGTAG, "unable to route jingle packet: " + packet);
             respondWithJingleError(account, packet, "unknown-session", "item-not-found", "cancel");
-
         }
     }
 
diff --git a/src/main/java/eu/siacs/conversations/xmpp/jingle/JingleRtpConnection.java b/src/main/java/eu/siacs/conversations/xmpp/jingle/JingleRtpConnection.java
index 6cc3f69a7..d03505fd8 100644
--- a/src/main/java/eu/siacs/conversations/xmpp/jingle/JingleRtpConnection.java
+++ b/src/main/java/eu/siacs/conversations/xmpp/jingle/JingleRtpConnection.java
@@ -30,6 +30,12 @@ import rocks.xmpp.addr.Jid;
 
 public class JingleRtpConnection extends AbstractJingleConnection implements WebRTCWrapper.EventCallback {
 
+    public static final List<State> STATES_SHOWING_ONGOING_CALL = Arrays.asList(
+            State.PROCEED,
+            State.SESSION_INITIALIZED,
+            State.SESSION_INITIALIZED_PRE_APPROVED,
+            State.SESSION_ACCEPTED
+    );
     private static final Map<State, Collection<State>> VALID_TRANSITIONS;
 
     static {
@@ -74,13 +80,6 @@ public class JingleRtpConnection extends AbstractJingleConnection implements Web
         VALID_TRANSITIONS = transitionBuilder.build();
     }
 
-    public static final List<State> STATES_SHOWING_ONGOING_CALL = Arrays.asList(
-            State.PROCEED,
-            State.SESSION_INITIALIZED,
-            State.SESSION_INITIALIZED_PRE_APPROVED,
-            State.SESSION_ACCEPTED
-    );
-
     private final WebRTCWrapper webRTCWrapper = new WebRTCWrapper(this);
     private final ArrayDeque<IceCandidate> pendingIceCandidates = new ArrayDeque<>();
     private State state = State.NULL;
@@ -196,7 +195,7 @@ public class JingleRtpConnection extends AbstractJingleConnection implements Web
             contentMap.requireDTLSFingerprint();
         } catch (final IllegalArgumentException | IllegalStateException | NullPointerException e) {
             respondOk(jinglePacket);
-            sendSessionTerminate(Reason.FAILED_APPLICATION);
+            sendSessionTerminate(Reason.FAILED_APPLICATION, e.getMessage());
             Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": improperly formatted contents", e);
             return;
         }
@@ -238,7 +237,7 @@ public class JingleRtpConnection extends AbstractJingleConnection implements Web
             respondOk(jinglePacket);
             Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": improperly formatted contents in session-accept", e);
             webRTCWrapper.close();
-            sendSessionTerminate(Reason.FAILED_APPLICATION);
+            sendSessionTerminate(Reason.FAILED_APPLICATION, e.getMessage());
             return;
         }
         Log.d(Config.LOGTAG, "processing session-accept with " + contentMap.contents.size() + " contents");