diff --git a/protocol/src/main/java/ch/zhaw/pm2/multichat/protocol/ConnectionHandler.java b/protocol/src/main/java/ch/zhaw/pm2/multichat/protocol/ConnectionHandler.java
index f7acd4a..f0e31bb 100644
--- a/protocol/src/main/java/ch/zhaw/pm2/multichat/protocol/ConnectionHandler.java
+++ b/protocol/src/main/java/ch/zhaw/pm2/multichat/protocol/ConnectionHandler.java
@@ -14,7 +14,7 @@ public abstract class ConnectionHandler {
     public static final String USER_ALL = "*";
 
     public enum State {
-        NEW, CONFIRM_CONNECT, CONNECTED, CONFIRM_DISCONNECT, DISCONNECTED;
+        NEW, CONFIRM_CONNECT, CONNECTED, CONFIRM_DISCONNECT, DISCONNECTED, ERROR;
     }
 
     public static String getDataTypeConnect() {
diff --git a/server/src/main/java/ch/zhaw/pm2/multichat/server/Server.java b/server/src/main/java/ch/zhaw/pm2/multichat/server/Server.java
index 7e31a36..7c447d6 100644
--- a/server/src/main/java/ch/zhaw/pm2/multichat/server/Server.java
+++ b/server/src/main/java/ch/zhaw/pm2/multichat/server/Server.java
@@ -1,5 +1,6 @@
 package ch.zhaw.pm2.multichat.server;
 
+import ch.zhaw.pm2.multichat.protocol.ConnectionHandler;
 import ch.zhaw.pm2.multichat.protocol.NetworkHandler;
 
 import java.io.IOException;
@@ -75,11 +76,17 @@ public class Server {
                  mutex.lock();
                  try {
                      nameComplete.await();
-                     System.out.println(String.format("Connected new Client %s with IP:Port <%s:%d>",
-                             connectionHandler.getUserName(),
-                             connection.getRemoteHost(),
-                             connection.getRemotePort()
-                     ));
+                     if(connectionHandler.getState() == ConnectionHandler.State.ERROR) {
+                         System.out.println(String.format("Connecting failed for new Client with IP:Port <%s:%d>.\nReason: Name already taken.",
+                                 connection.getRemoteHost(),
+                                 connection.getRemotePort()));
+                     }
+                     else {
+                         System.out.println(String.format("Connected new Client %s with IP:Port <%s:%d>",
+                                 connectionHandler.getUserName(),
+                                 connection.getRemoteHost(),
+                                 connection.getRemotePort()));
+                     }
                  }
                 finally {
                      mutex.unlock();
diff --git a/server/src/main/java/ch/zhaw/pm2/multichat/server/ServerConnectionHandler.java b/server/src/main/java/ch/zhaw/pm2/multichat/server/ServerConnectionHandler.java
index c911b7b..c45dfca 100644
--- a/server/src/main/java/ch/zhaw/pm2/multichat/server/ServerConnectionHandler.java
+++ b/server/src/main/java/ch/zhaw/pm2/multichat/server/ServerConnectionHandler.java
@@ -50,11 +50,15 @@ public class ServerConnectionHandler extends ConnectionHandler implements Runnab
         return this.userName;
     }
 
+    public State getState() {
+        return state;
+    }
+
     private void startReceiving() {
             System.out.println("Starting Connection Handler for new User");
             try {
                 System.out.println("Start receiving data...");
-                while (getConnection().isAvailable()) {
+                while (getConnection().isAvailable() && !(state == ERROR)) {
                     String data = getConnection().receive();
                     processData(data);
                 }
@@ -72,7 +76,11 @@ public class ServerConnectionHandler extends ConnectionHandler implements Runnab
             } catch (ClassNotFoundException e) {
                 System.err.println("Received object of unknown type: " + e.getMessage());
             }
+        if (state == ERROR) {
+            System.out.println("Stopping Connection Handler for Rejected Client");
+        } else {
             System.out.println("Stopping Connection Handler for " + userName);
+        }
 
     }
 
@@ -119,8 +127,17 @@ public class ServerConnectionHandler extends ConnectionHandler implements Runnab
             if (type.equals(getDataTypeConnect())) {
                 if (this.state != NEW) throw new ChatProtocolException("Illegal state for connect request: " + state);
                 if (sender == null || sender.isBlank()) sender = this.userName;
-                if (connectionRegistry.containsKey(sender))
+                if (connectionRegistry.containsKey(sender)) {
+                    mutex.lock();
+                    try {
+                        state = ERROR;
+                        nameComplete.signal();
+                    }
+                    finally {
+                        mutex.unlock();
+                    }
                     throw new ChatProtocolException("User name already taken: " + sender);
+                }
                 mutex.lock();
                 try {
                     this.userName = sender;
@@ -167,11 +184,13 @@ public class ServerConnectionHandler extends ConnectionHandler implements Runnab
 
             }
         } catch(ChatProtocolException e) {
-            System.out.println("Error while processing data" + e.getMessage());
+            System.out.println("Error while processing data " + e.getMessage());
             sendData(USER_NONE, userName, getDataTypeError(), e.getMessage());
         }
     }
 
+
+
     private void sendData(String sender, String receiver, String type, String payload) {
         if (getConnection().isAvailable()) {
             new StringBuilder();