diff --git a/static/stemp_abw/foundation/css/app.css b/static/stemp_abw/foundation/css/app.css
index 4fcb1246..f503700f 100644
--- a/static/stemp_abw/foundation/css/app.css
+++ b/static/stemp_abw/foundation/css/app.css
@@ -1888,6 +1888,13 @@ footer.map-footer {
   #saveSimulation p {
     font-weight: 700; }
 
+#errorMessage {
+  text-align: center;}
+  #errorMessage h2 {
+    color: #ff0000;}
+  #errorMessage p {
+    font-weight: 700;}
+
 #results-wrap {
   margin-top: 1.55rem; }
   #results-wrap .tabs {
diff --git a/static/stemp_abw/js/data_functions.js b/static/stemp_abw/js/data_functions.js
index 5c58f088..af224721 100644
--- a/static/stemp_abw/js/data_functions.js
+++ b/static/stemp_abw/js/data_functions.js
@@ -24,6 +24,7 @@ function ctrlScenario(element_id) {
     },
     error: function(page) {
         console.log('error');
+        showErrorPopup();
     }
   }).done(function(returned_data) {
     if (element_id == 'select-scn-frm') {
@@ -59,6 +60,7 @@ function ctrlScenarioPost(element_id, data) {
     },
     error: function(page) {
         console.log('error');
+        showErrorPopup();
     }
   }).done(function(returned_data) {
     data = JSON.parse(returned_data);
@@ -87,6 +89,7 @@ function ctrlSimulate() {
       },
       error: function(page) {
           console.log('error');
+          showErrorPopup();
       }
   }).done(function(returned_data){
       //updateSimProgressBar(25);
@@ -146,6 +149,10 @@ function getSimulationResults() {
                 Highcharts.charts[idx2].hideLoading();
             };
         },
+        error: function(page) {
+            console.log('error');
+            showErrorPopup();
+        },
         cache: false
     });
 }
diff --git a/static/stemp_abw/js/ui_helpers.js b/static/stemp_abw/js/ui_helpers.js
index f377c95e..dabae1ef 100644
--- a/static/stemp_abw/js/ui_helpers.js
+++ b/static/stemp_abw/js/ui_helpers.js
@@ -102,4 +102,9 @@ $('.openEnergyTab').on('click', openEnergyTab);
 //
 //$('.tabs-title').click( function () {
 //  $('#' + $(this).attr('id') + ' > a').removeClass('tab-highlighted');
-//});
\ No newline at end of file
+//});
+
+// Show a popup with error message
+function showErrorPopup() {
+  $('#errorMessage').foundation('open');
+}
\ No newline at end of file
diff --git a/templates/stemp_abw/map.html b/templates/stemp_abw/map.html
index 2dd0e952..40686f61 100644
--- a/templates/stemp_abw/map.html
+++ b/templates/stemp_abw/map.html
@@ -455,6 +455,11 @@ <h2 class="tabs-title__head">Ergebnisse</h2>
       </div>
     </footer>
 
+    <div class="tiny reveal" id="errorMessage" data-reveal>
+      <h2>Fehler</h2>
+      <p>Es ist ein Fehler aufgetreten. Bitte starten Sie das Tool neu.</p>
+    </div>
+
     <!-- START POP-UP RESULTS -->
     <div class="large reveal" id="resultsModal" data-reveal>
       <button class="close-button" data-close aria-label="Close modal" type="button">