diff --git a/src/BreCalClient/MainWindow.xaml.cs b/src/BreCalClient/MainWindow.xaml.cs
index 9389a70..34175a2 100644
--- a/src/BreCalClient/MainWindow.xaml.cs
+++ b/src/BreCalClient/MainWindow.xaml.cs
@@ -133,7 +133,10 @@ namespace BreCalClient
             {
                 if ((ex.ErrorContent != null && ((string)ex.ErrorContent).StartsWith("{"))) {
                     Error? anError = JsonConvert.DeserializeObject<Error>((string)ex.ErrorContent);
-                    this.labelLoginResult.Content = anError?.Message ?? ex.Message;
+                    if ((anError != null) && anError.Message.Equals("invalid credentials"))
+                        this.labelLoginResult.Content = BreCalClient.Resources.Resources.textWrongCredentials;
+                    else
+                        this.labelLoginResult.Content = anError?.Message ?? ex.Message;
                 }
                 else {
                     this.labelLoginResult.Content = ex.Message;
diff --git a/src/BreCalClient/Resources/Resources.Designer.cs b/src/BreCalClient/Resources/Resources.Designer.cs
index 84e9ae1..99a3e26 100644
--- a/src/BreCalClient/Resources/Resources.Designer.cs
+++ b/src/BreCalClient/Resources/Resources.Designer.cs
@@ -940,6 +940,15 @@ namespace BreCalClient.Resources {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Wrong username or password.
+        /// </summary>
+        public static string textWrongCredentials {
+            get {
+                return ResourceManager.GetString("textWrongCredentials", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Zone entry.
         /// </summary>
diff --git a/src/BreCalClient/Resources/Resources.de.resx b/src/BreCalClient/Resources/Resources.de.resx
index c921646..b3b04f0 100644
--- a/src/BreCalClient/Resources/Resources.de.resx
+++ b/src/BreCalClient/Resources/Resources.de.resx
@@ -415,4 +415,7 @@
   <data name="textPhone" xml:space="preserve">
     <value>Telefon</value>
   </data>
+  <data name="textWrongCredentials" xml:space="preserve">
+    <value>Benutzername / Passwort falsch</value>
+  </data>
 </root>
\ No newline at end of file
diff --git a/src/BreCalClient/Resources/Resources.resx b/src/BreCalClient/Resources/Resources.resx
index 181c6d1..701f0cf 100644
--- a/src/BreCalClient/Resources/Resources.resx
+++ b/src/BreCalClient/Resources/Resources.resx
@@ -406,6 +406,9 @@
   <data name="textWidth" xml:space="preserve">
     <value>Width</value>
   </data>
+  <data name="textWrongCredentials" xml:space="preserve">
+    <value>Wrong username or password</value>
+  </data>
   <data name="textZoneEntryTime" xml:space="preserve">
     <value>Zone entry</value>
   </data>