diff --git a/src/net/java/sip/communicator/impl/protocol/sip/SipRegistrarConnection.java b/src/net/java/sip/communicator/impl/protocol/sip/SipRegistrarConnection.java
index 1906b5b81..e96104882 100644
--- a/src/net/java/sip/communicator/impl/protocol/sip/SipRegistrarConnection.java
+++ b/src/net/java/sip/communicator/impl/protocol/sip/SipRegistrarConnection.java
@@ -939,10 +939,17 @@ else if ( response.getStatusCode() >= 400 )
         {
             logger.error("Received an error response.");
 
+            int registrationStateReason =
+                RegistrationStateChangeEvent.REASON_NOT_SPECIFIED;
+
+            if(response.getStatusCode() == Response.NOT_FOUND)
+                registrationStateReason =
+                    RegistrationStateChangeEvent.REASON_NON_EXISTING_USER_ID;
+
             //tell the others we couldn't register
             this.setRegistrationState(
                 RegistrationState.CONNECTION_FAILED
-                , RegistrationStateChangeEvent.REASON_NOT_SPECIFIED
+                , registrationStateReason
                 , "Received an error while trying to register. "
                 + "Server returned error:" + response.getReasonPhrase()
             );
diff --git a/src/net/java/sip/communicator/plugin/reconnectplugin/ReconnectPluginActivator.java b/src/net/java/sip/communicator/plugin/reconnectplugin/ReconnectPluginActivator.java
index fc8222e6c..7f26eb627 100644
--- a/src/net/java/sip/communicator/plugin/reconnectplugin/ReconnectPluginActivator.java
+++ b/src/net/java/sip/communicator/plugin/reconnectplugin/ReconnectPluginActivator.java
@@ -574,13 +574,25 @@ public synchronized void registrationStateChanged(RegistrationStateChangeEvent e
                 {
                     // ignore providers which haven't registered successfully
                     // till now, they maybe misconfigured
-                    // todo show dialog
-                    notify(
-                        getResources().getI18NString("service.gui.ERROR"),
-                        "plugin.reconnectplugin.CONNECTION_FAILED_MSG",
-                        new String[]
-                        {   pp.getAccountID().getUserID(),
-                            pp.getAccountID().getService() });
+                    String notifyMsg;
+
+                    if(evt.getReasonCode() ==
+                        RegistrationStateChangeEvent.REASON_NON_EXISTING_USER_ID)
+                    {
+                        notify(
+                            getResources().getI18NString("service.gui.ERROR"),
+                            "service.gui.NON_EXISTING_USER_ID",
+                            new String[]{pp.getAccountID().getService()});
+                    }
+                    else
+                    {
+                        notify(
+                            getResources().getI18NString("service.gui.ERROR"),
+                            "plugin.reconnectplugin.CONNECTION_FAILED_MSG",
+                            new String[]
+                            {   pp.getAccountID().getUserID(),
+                                pp.getAccountID().getService() });
+                    }
 
                     return;
                 }