Handle nonexistent PLZs

templates/offer/index.html.twig

@@ -9,6 +9,11 @@
         {{ message }}
     </div>
     {% endfor %}
+    {% for message in app.flashes('error') %}
+    <div class="alert alert-danger" role="alert">
+        {{ message }}
+    </div>
+    {% endfor %}
 
     <h2><i class="fas fa-filter"></i>Filter</h2>
     {{ form_start(filter_form) }}
@@ -53,6 +58,6 @@
             {% endfor %}
         </div>
     {% else %}
-        <div class="alert alert-warning" role="alert">There are currently no active offers.</div>
+        <div class="alert alert-warning" role="alert">There are no active offers with the current filter.</div>
     {% endif %}
 {% endblock %}