diff --git a/project/static/jquery.recurrenceinput.js b/project/static/jquery.recurrenceinput.js
index be0f64e..502de4d 100644
--- a/project/static/jquery.recurrenceinput.js
+++ b/project/static/jquery.recurrenceinput.js
@@ -1354,7 +1354,7 @@
                     element.find('.rioccurrences').show();
                 },
                 error: function (jqXHR, textStatus, errorThrown) {
-                    alert(textStatus);
+                    alert(textStatus + " " + jqXHR.statusText + " " + jqXHR.responseText);
                 }
             };
 
diff --git a/project/views/event.py b/project/views/event.py
index 5ff131c..f0efb84 100644
--- a/project/views/event.py
+++ b/project/views/event.py
@@ -275,10 +275,14 @@ def event_rrule():
 
     from project.dateutils import calculate_occurrences
 
-    result = calculate_occurrences(
-        start_date, '"%d.%m.%Y"', rrule_str, start, batch_size
-    )
-    return jsonify(result)
+    try:
+        result = calculate_occurrences(
+            start_date, '"%d.%m.%Y"', rrule_str, start, batch_size
+        )
+        return jsonify(result)
+    except Exception as e:
+        app.logger.exception(request.json)
+        return str(e), 400
 
 
 def get_event_category_choices():
diff --git a/tests/views/test_event.py b/tests/views/test_event.py
index d80256a..23fd880 100644
--- a/tests/views/test_event.py
+++ b/tests/views/test_event.py
@@ -643,6 +643,21 @@ def test_rrule(client, seeder, utils, app):
     assert occurence["formattedDate"] == '"25.11.2020"'
 
 
+def test_rrule_bad_request(client, seeder, utils, app):
+    url = utils.get_url("event_rrule")
+    response = utils.post_json(
+        url,
+        {
+            "year": 2020,
+            "month": 11,
+            "day": 25,
+            "rrule": "RRULE:FREQ=DAILY;COUNT=7bad",
+            "start": 0,
+        },
+    )
+    utils.assert_response_bad_request(response)
+
+
 def test_report(seeder, utils):
     user_id, admin_unit_id = seeder.setup_base()
     event_id = seeder.create_event(admin_unit_id)