diff --git a/app.py b/app.py
index ade3a56..e9ee88b 100644
--- a/app.py
+++ b/app.py
@@ -165,9 +165,21 @@ def admin(instance_id):
         
     auth_key = f'admin_auth_{instance_id}'
     
+    # Check if instance has no password (empty or None)
+    stored_password = instance['password']
+    has_no_password = (
+        stored_password is None or
+        check_password_hash(stored_password, '')
+    )
+
     # Handle Login Submission
     if request.method == "POST" and 'admin_password' in request.form:
-        if check_password_hash(instance['password'], request.form['admin_password']):
+        entered = request.form['admin_password']
+        if has_no_password and entered == '':
+            session[auth_key] = True
+            conn.close()
+            return redirect(url_for('admin', instance_id=instance_id))
+        elif not has_no_password and check_password_hash(stored_password, entered):
             session[auth_key] = True
             conn.close()
             return redirect(url_for('admin', instance_id=instance_id))
diff --git a/templates/login.html b/templates/login.html
index 3dd0096..3493d47 100644
--- a/templates/login.html
+++ b/templates/login.html
@@ -22,9 +22,9 @@
 
         <form method="post" class="bg-white p-4 shadow-sm rounded">
             <div class="form-group">
-                <label for="admin_password">Passworteingabe erforderlich</label>
-                <input type="password" class="form-control" name="admin_password" id="admin_password" required
-                    autofocus>
+                <label for="admin_password">Passwort (bei passwortloser Kasse leer lassen)</label>
+                <input type="password" class="form-control" name="admin_password" id="admin_password"
+                    autofocus placeholder="Leer lassen wenn keine Kasse mit Passwort">
             </div>
             <button type="submit" class="btn btn-primary w-100">Einloggen</button>
             <a href="{{ url_for('index', instance_id=instance_id) }}" class="btn btn-secondary w-100 mt-2">Zurück zur