diff --git a/CHANGES.rst b/CHANGES.rst
index 8915e4d..8ddae44 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -4,7 +4,8 @@ Changelog
 5.2.1 (unreleased)
 ------------------
 
-- Nothing changed yet.
+- Ignore non-existing indexes in custom ranking.
+  [cekk]
 
 
 5.2.0 (2023-08-21)
diff --git a/src/redturtle/volto/restapi/services/search/get.py b/src/redturtle/volto/restapi/services/search/get.py
index 30541cf..12b61a0 100644
--- a/src/redturtle/volto/restapi/services/search/get.py
+++ b/src/redturtle/volto/restapi/services/search/get.py
@@ -90,10 +90,15 @@ def search(self, query=None):
                         queries.append(Eq(key, value["query"]))
                 elif key in ("b_start", "b_size"):
                     continue
+                elif index_type is None:
+                    # skip, non-existent index
+                    continue
                 else:
                     logger.warning(
                         f"Unsupported query parameter: {key} {index_type} {value}. Fall back to the standard query."
                     )
+                    query = self.request.form.copy()
+                    query = unflatten_dotted_dict(query)
                     return super(SearchHandler, self).search(query)
 
             # term = query.pop("SearchableText")
@@ -118,8 +123,7 @@ def search(self, query=None):
             )
 
             return results
-        else:
-            return super(SearchHandler, self).search(query)
+        return super(SearchHandler, self).search(query)
 
     def _parse_query(self, query):
         query = super()._parse_query(query)
diff --git a/src/redturtle/volto/tests/test_advancedsearch.py b/src/redturtle/volto/tests/test_advancedsearch.py
index e792da2..b7ffc95 100644
--- a/src/redturtle/volto/tests/test_advancedsearch.py
+++ b/src/redturtle/volto/tests/test_advancedsearch.py
@@ -166,6 +166,34 @@ def test_search_by_not_handled_index_type_return_standard_order(self):
             ["f1", "d1", "e1"], [item["@id"].split("/")[-1] for item in result["items"]]
         )
 
+    def test_search_ignore_non_existent_indexes_and_return_custom_order_if_possible(
+        self,
+    ):
+        response = self.api_session.get(
+            "/@search", params={"SearchableText": "foo", "xxx": True}
+        )
+        result = response.json()
+        self.assertEqual(result["items_total"], 3)
+        self.assertEqual(
+            ["d1", "f1", "e1"], [item["@id"].split("/")[-1] for item in result["items"]]
+        )
+
+        # now repeat query with not handled index, and return standard order
+        response = self.api_session.get(
+            "/@search",
+            params={
+                "SearchableText": "foo",
+                "created.query": f"{DateTime().Date()}:00:00",
+                "created.range": "min",
+                "xxx": True,
+            },
+        )
+        result = response.json()
+        self.assertEqual(result["items_total"], 3)
+        self.assertEqual(
+            ["f1", "d1", "e1"], [item["@id"].split("/")[-1] for item in result["items"]]
+        )
+
 
 class AdvancedSearchWithFlagTest(BaseTest):
     def test_by_default_flag_is_disabled(self):