diff --git a/Mage.Server/src/main/java/mage/server/ChatSession.java b/Mage.Server/src/main/java/mage/server/ChatSession.java
index 46b3018290..41b92d70dd 100644
--- a/Mage.Server/src/main/java/mage/server/ChatSession.java
+++ b/Mage.Server/src/main/java/mage/server/ChatSession.java
@@ -65,7 +65,7 @@ public class ChatSession {
 	}
 
 	public void kill(UUID userId) {
-		if (clients.containsKey(userId)) {
+		if (userId != null && clients.containsKey(userId)) {
 			String userName = clients.get(userId);
 			clients.remove(userId);
 			broadcast(userName, " has left", MessageColor.BLACK);
diff --git a/Mage.Server/src/main/java/mage/server/MageServerImpl.java b/Mage.Server/src/main/java/mage/server/MageServerImpl.java
index db03630709..3b14896440 100644
--- a/Mage.Server/src/main/java/mage/server/MageServerImpl.java
+++ b/Mage.Server/src/main/java/mage/server/MageServerImpl.java
@@ -451,8 +451,11 @@ public class MageServerImpl implements MageServer {
 	@Override
 	public boolean isTableOwner(String sessionId, UUID roomId, UUID tableId) throws MageException {
 		try {
-			UUID userId = SessionManager.getInstance().getSession(sessionId).getUserId();
-			return TableManager.getInstance().isTableOwner(tableId, userId);
+            Session session = SessionManager.getInstance().getSession(sessionId);
+            if (session != null) {
+                UUID userId = SessionManager.getInstance().getSession(sessionId).getUserId();
+                return TableManager.getInstance().isTableOwner(tableId, userId);
+            }
 		}
 		catch (Exception ex) {
 			handleException(ex);
diff --git a/Mage.Server/src/main/java/mage/server/TableController.java b/Mage.Server/src/main/java/mage/server/TableController.java
index 3731a868e9..83408474ce 100644
--- a/Mage.Server/src/main/java/mage/server/TableController.java
+++ b/Mage.Server/src/main/java/mage/server/TableController.java
@@ -263,7 +263,8 @@ public class TableController {
 		else {
 			player = PlayerFactory.getInstance().createPlayer(playerType, name, options.getRange(), skill);
 		}
-		logger.info("Player created " + player.getId());
+        if (player != null)
+            logger.info("Player created " + player.getId());
 		return player;
 	}
 
diff --git a/Mage.Server/src/main/java/mage/server/User.java b/Mage.Server/src/main/java/mage/server/User.java
index 58c106d0a9..5a4d75726f 100644
--- a/Mage.Server/src/main/java/mage/server/User.java
+++ b/Mage.Server/src/main/java/mage/server/User.java
@@ -119,7 +119,8 @@ public class User {
 	public synchronized void fireCallback(final ClientCallback call) {
 		if (isConnected()) {
 			Session session = SessionManager.getInstance().getSession(sessionId);
-			session.fireCallback(call);		
+            if (session != null)
+                session.fireCallback(call);		
 		}
 	}
 
diff --git a/Mage.Server/src/main/java/mage/server/tournament/TournamentController.java b/Mage.Server/src/main/java/mage/server/tournament/TournamentController.java
index c4c21e1fad..c38805603a 100644
--- a/Mage.Server/src/main/java/mage/server/tournament/TournamentController.java
+++ b/Mage.Server/src/main/java/mage/server/tournament/TournamentController.java
@@ -217,11 +217,15 @@ public class TournamentController {
 	}
 
 	public void submitDeck(UUID playerId, Deck deck) {
-		tournamentSessions.get(playerId).submitDeck(deck);
+		if (tournamentSessions.containsKey(playerId)) {
+    		tournamentSessions.get(playerId).submitDeck(deck);
+        }
 	}
 
 	public void updateDeck(UUID playerId, Deck deck) {
-		tournamentSessions.get(playerId).updateDeck(deck);
+		if (tournamentSessions.containsKey(playerId)) {
+    		tournamentSessions.get(playerId).updateDeck(deck);
+        }
 	}
 
     public void timeout(UUID userId) {