diff --git a/app/src/main/java/it/niedermann/owncloud/notes/android/activity/NotesListViewActivity.java b/app/src/main/java/it/niedermann/owncloud/notes/android/activity/NotesListViewActivity.java
index 022b180c5..4813188a3 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/android/activity/NotesListViewActivity.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/android/activity/NotesListViewActivity.java
@@ -105,7 +105,9 @@ public void onFinish() {
                 adapter.checkForUpdates(db.getNotes());
             }
         });
-        db.getNoteServerSyncHelper().downloadNotes();
+        if (!PreferenceManager.getDefaultSharedPreferences(getApplicationContext()).getBoolean(SettingsActivity.SETTINGS_FIRST_RUN, true)) {
+            db.getNoteServerSyncHelper().downloadNotes();
+        }
         super.onResume();
     }
 
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/android/activity/SettingsActivity.java b/app/src/main/java/it/niedermann/owncloud/notes/android/activity/SettingsActivity.java
index 702eb395a..953d064f7 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/android/activity/SettingsActivity.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/android/activity/SettingsActivity.java
@@ -20,6 +20,7 @@
 
 import it.niedermann.owncloud.notes.R;
 import it.niedermann.owncloud.notes.util.NotesClientUtil;
+import it.niedermann.owncloud.notes.util.NotesClientUtil.LoginStatus;
 
 /**
  * Allows to set Settings like URL, Username and Password for Server-Synchronization
@@ -194,7 +195,7 @@ protected void onPostExecute(Boolean o) {
     /**
      * If Log-In-Credentials are correct, save Credentials to Shared Preferences and finish First Run Wizard.
      */
-    private class LoginValidatorAsyncTask extends AsyncTask<String, Void, Boolean> {
+    private class LoginValidatorAsyncTask extends AsyncTask<String, Void, LoginStatus> {
         String url, username, password;
 
         @Override
@@ -208,7 +209,7 @@ protected void onPreExecute() {
          * @return isValidLogin Boolean
          */
         @Override
-        protected Boolean doInBackground(String... params) {
+        protected LoginStatus doInBackground(String... params) {
             url = params[0];
             username = params[1];
             password = params[2];
@@ -216,8 +217,8 @@ protected Boolean doInBackground(String... params) {
         }
 
         @Override
-        protected void onPostExecute(Boolean isValidLogin) {
-            if (isValidLogin) {
+        protected void onPostExecute(LoginStatus status) {
+            if (LoginStatus.OK.equals(status)) {
                 SharedPreferences.Editor editor = preferences.edit();
                 editor.putString(SETTINGS_URL, url);
                 editor.putString(SETTINGS_USERNAME, username);
@@ -238,7 +239,7 @@ protected void onPostExecute(Boolean isValidLogin) {
                 Log.e("Note", "invalid login");
                 btn_submit.setText(R.string.settings_submit);
                 setInputsEnabled(true);
-                Toast.makeText(getApplicationContext(), getString(R.string.error_invalid_login), Toast.LENGTH_LONG).show();
+                Toast.makeText(getApplicationContext(), getString(R.string.error_invalid_login, getString(status.str)), Toast.LENGTH_LONG).show();
             }
         }
 
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/NoteServerSyncHelper.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/NoteServerSyncHelper.java
index 019ed6e4f..f82db47ab 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/persistence/NoteServerSyncHelper.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/persistence/NoteServerSyncHelper.java
@@ -1,6 +1,7 @@
 package it.niedermann.owncloud.notes.persistence;
 
 import android.app.Activity;
+import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.os.AsyncTask;
@@ -8,6 +9,7 @@
 import android.os.Message;
 import android.preference.PreferenceManager;
 import android.view.View;
+import android.widget.Toast;
 
 import org.json.JSONException;
 
@@ -15,11 +17,13 @@
 import java.util.ArrayList;
 import java.util.List;
 
+import it.niedermann.owncloud.notes.R;
 import it.niedermann.owncloud.notes.android.activity.SettingsActivity;
 import it.niedermann.owncloud.notes.model.DBStatus;
 import it.niedermann.owncloud.notes.model.Note;
 import it.niedermann.owncloud.notes.util.ICallback;
 import it.niedermann.owncloud.notes.util.NotesClient;
+import it.niedermann.owncloud.notes.util.NotesClientUtil.LoginStatus;
 
 /**
  * Helps to synchronize the Database to the Server.
@@ -205,7 +209,7 @@ protected void onPostExecute(Void aVoid) {
     }
 
     private class DownloadNotesTask extends AsyncTask<Object, Void, List<Note>> {
-        private boolean serverError = false;
+        private LoginStatus status = null;
 
         @Override
         protected List<Note> doInBackground(Object... params) {
@@ -213,9 +217,12 @@ protected List<Note> doInBackground(Object... params) {
             List<Note> notes = new ArrayList<>();
             try {
                 notes = client.getNotes();
-            } catch (IOException | JSONException e) {
-                serverError = true;
+                status = LoginStatus.OK;
+            } catch (IOException e) {
                 e.printStackTrace();
+                status = LoginStatus.CONNECTION_FAILED;
+            } catch (JSONException e) {
+                status = LoginStatus.JSON_FAILED;
             }
             return notes;
         }
@@ -223,8 +230,11 @@ protected List<Note> doInBackground(Object... params) {
         @Override
         protected void onPostExecute(List<Note> result) {
             // Clear Database only if there was no Server Error
-            if (!serverError) {
+            if (status==LoginStatus.OK) {
                 db.clearDatabase();
+            } else {
+                Context c = db.getContext();
+                Toast.makeText(c, c.getString(R.string.error_sync, c.getString(status.str)), Toast.LENGTH_LONG).show();
             }
             for (Note note : result) {
                 db.addNote(note);
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/util/NotesClientUtil.java b/app/src/main/java/it/niedermann/owncloud/notes/util/NotesClientUtil.java
index b52a51835..16801f7c2 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/util/NotesClientUtil.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/util/NotesClientUtil.java
@@ -2,6 +2,7 @@
 
 import android.util.Base64;
 
+import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
@@ -12,12 +13,27 @@
 import java.net.MalformedURLException;
 import java.net.URL;
 
+import it.niedermann.owncloud.notes.R;
+
 /**
  * Utils for Validation etc
  * Created by stefan on 25.09.15.
  */
 public class NotesClientUtil {
 
+    public enum LoginStatus {
+        OK(0),
+        AUTH_FAILED(R.string.error_username_password_invalid),
+        CONNECTION_FAILED(R.string.error_io),
+        JSON_FAILED(R.string.error_json),
+        SERVER_FAILED(R.string.error_server);
+
+        public final int str;
+        LoginStatus(int str) {
+            this.str = str;
+        }
+    }
+
     /**
      * Checks if the given url String starts with http:// or https://
      *
@@ -34,7 +50,7 @@ public static boolean isHttp(String url) {
      * @param password String
      * @return Username and Password are a valid Login-Combination for the given URL.
      */
-    public static boolean isValidLogin(String url, String username, String password) {
+    public static LoginStatus isValidLogin(String url, String username, String password) {
         try {
             String targetURL = url + "index.php/apps/notes/api/v0.2/notes";
             HttpURLConnection con = (HttpURLConnection) new URL(targetURL)
@@ -48,14 +64,27 @@ public static boolean isValidLogin(String url, String username, String password)
             con.setConnectTimeout(10 * 1000); // 10 seconds
             con.connect();
             if (con.getResponseCode() == 200) {
-                return true;
+                StringBuilder result = new StringBuilder();
+                BufferedReader rd = new BufferedReader(new InputStreamReader(con.getInputStream()));
+                String line;
+                while ((line = rd.readLine()) != null) {
+                    result.append(line);
+                }
+                System.out.println(result.toString());
+                new JSONArray(result.toString());
+                return LoginStatus.OK;
+            } else if (con.getResponseCode() >= 401 && con.getResponseCode() <= 403) {
+                return LoginStatus.AUTH_FAILED;
+            } else {
+                return LoginStatus.SERVER_FAILED;
             }
-        } catch (MalformedURLException e1) {
-            return false;
+        } catch (MalformedURLException e) {
+            return LoginStatus.CONNECTION_FAILED;
         } catch (IOException e) {
-            return false;
+            return LoginStatus.CONNECTION_FAILED;
+        } catch (JSONException e) {
+            return LoginStatus.JSON_FAILED;
         }
-        return false;
     }
 
     /**
@@ -65,7 +94,7 @@ public static boolean isValidLogin(String url, String username, String password)
      * @return true if there is a installed instance, false if not
      */
     public static boolean isValidURL(String url) {
-        StringBuffer result = new StringBuffer();
+        StringBuilder result = new StringBuilder();
         try {
             HttpURLConnection con = (HttpURLConnection) new URL(url + "status.php")
                     .openConnection();
diff --git a/app/src/main/res/values-de/strings.xml b/app/src/main/res/values-de/strings.xml
index 8f3123fbe..a936fb8e2 100644
--- a/app/src/main/res/values-de/strings.xml
+++ b/app/src/main/res/values-de/strings.xml
@@ -45,9 +45,11 @@
     <string name="network_disconnected">Kein Netzwerk verfügbar</string>
 
     <!-- Error -->
-    <string name="error_json">JSON-Fehler</string>
-    <string name="error_io">IO-Fehler</string>
-    <string name="error_invalid_login">Login fehlgeschlagen</string>
+    <string name="error_sync">Synchronisation fehlgeschlagen: %1$s</string>
+    <string name="error_invalid_login">Login fehlgeschlagen: %1$s</string>
+    <string name="error_json">ist die Server-App ownCloud Notes aktiviert?</string>
+    <string name="error_io">Server-Verbindung nicht möglich</string>
+    <string name="error_server">URL/Server fehlerhaft</string>
     <string name="error_url_malformed">URL nicht korrekt</string>
     <string name="error_username_password_invalid">Benutzername / Passwort nicht korrekt</string>
 
diff --git a/app/src/main/res/values-fr/strings.xml b/app/src/main/res/values-fr/strings.xml
index 1fc657a2e..3c4c91b9a 100644
--- a/app/src/main/res/values-fr/strings.xml
+++ b/app/src/main/res/values-fr/strings.xml
@@ -47,7 +47,7 @@
     <!-- Error -->
     <string name="error_json">Erreur de JSON</string>
     <string name="error_io">Erreur d\'E/S</string>
-    <string name="error_invalid_login">Détails de connexion incorrects</string>
+    <string name="error_invalid_login">Détails de connexion incorrects: %1$s</string>
     <string name="error_url_malformed">Adresse du serveur incorrecte</string>
     <string name="error_username_password_invalid">Identifiant ou mot de passe incorrect</string>
 
diff --git a/app/src/main/res/values-ru/strings.xml b/app/src/main/res/values-ru/strings.xml
index 90dfd626c..ed34806bc 100644
--- a/app/src/main/res/values-ru/strings.xml
+++ b/app/src/main/res/values-ru/strings.xml
@@ -47,7 +47,7 @@
     <string name="network_disconnected">Сеть недоступна</string>
 
     <!-- Error -->
-    <string name="error_invalid_login">Неверный логин</string>
+    <string name="error_invalid_login">Неверный логин: %1$s</string>
     <string name="error_io">Ошибка ввода/вывода</string>
     <string name="error_json">Ошибка JSON</string>
     <string name="error_url_malformed">Неверный адрес</string>
@@ -85,4 +85,4 @@
 
     <string name="widget_all_notes_title">Все заметки</string>
     <string name="widget_single_note_title">Одна заметка</string>
-</resources>
\ No newline at end of file
+</resources>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index ecdee1abe..26a8684ac 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -45,9 +45,11 @@
     <string name="network_disconnected">No network available</string>
 
     <!-- Error -->
-    <string name="error_json">JSON error</string>
-    <string name="error_io">IO error</string>
-    <string name="error_invalid_login">Invalid login</string>
+    <string name="error_sync">Synchronization failed: %1$s</string>
+    <string name="error_invalid_login">Invalid login: %1$s</string>
+    <string name="error_json">is the owncloud Notes app activated on the server?</string>
+    <string name="error_io">server connection is broken</string>
+    <string name="error_server">URL/Server has errors</string>
     <string name="error_url_malformed">Wrong server address</string>
     <string name="error_username_password_invalid">Wrong username or password</string>