diff --git a/server/src/main/java/org/elasticsearch/search/aggregations/bucket/histogram/DateIntervalWrapper.java b/server/src/main/java/org/elasticsearch/search/aggregations/bucket/histogram/DateIntervalWrapper.java
index b86989fce168d..b08782f1fd37a 100644
--- a/server/src/main/java/org/elasticsearch/search/aggregations/bucket/histogram/DateIntervalWrapper.java
+++ b/server/src/main/java/org/elasticsearch/search/aggregations/bucket/histogram/DateIntervalWrapper.java
@@ -288,11 +288,15 @@ public Rounding createRounding(ZoneId timeZone) {
         } else {
             // We're not sure what the interval was originally (legacy) so use old behavior of assuming
             // calendar first, then fixed.  Required because fixed/cal overlap in places ("1h")
-            DateTimeUnit intervalAsUnit = tryIntervalAsCalendarUnit();
-            if (intervalAsUnit != null) {
-                tzRoundingBuilder = Rounding.builder(tryIntervalAsCalendarUnit());
+            DateTimeUnit calInterval = tryIntervalAsCalendarUnit();
+            TimeValue fixedInterval = tryIntervalAsFixedUnit();
+            if (calInterval != null) {
+                tzRoundingBuilder = Rounding.builder(calInterval);
+            } else if (fixedInterval != null) {
+                tzRoundingBuilder = Rounding.builder(fixedInterval);
             } else {
-                tzRoundingBuilder = Rounding.builder(tryIntervalAsFixedUnit());
+                // If we get here we have exhausted our options and are not able to parse this interval
+                throw new IllegalArgumentException("Unable to parse interval [" + dateHistogramInterval + "]");
             }
         }
         if (timeZone != null) {
diff --git a/server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/DateHistogramAggregatorTests.java b/server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/DateHistogramAggregatorTests.java
index f671b21eb5e9b..17581b9458413 100644
--- a/server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/DateHistogramAggregatorTests.java
+++ b/server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/DateHistogramAggregatorTests.java
@@ -1097,6 +1097,16 @@ public void testLegacyThenNew() throws IOException {
         assertWarnings("[interval] on [date_histogram] is deprecated, use [fixed_interval] or [calendar_interval] in the future.");
     }
 
+    public void testIllegalInterval() throws IOException {
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> testSearchCase(new MatchAllDocsQuery(),
+            Collections.emptyList(),
+            aggregation -> aggregation.dateHistogramInterval(new DateHistogramInterval("foobar")).field(DATE_FIELD),
+            histogram -> {}
+        ));
+        assertThat(e.getMessage(), equalTo("Unable to parse interval [foobar]"));
+        assertWarnings("[interval] on [date_histogram] is deprecated, use [fixed_interval] or [calendar_interval] in the future.");
+    }
+
     private void testSearchCase(Query query, List<String> dataset,
                                 Consumer<DateHistogramAggregationBuilder> configure,
                                 Consumer<InternalDateHistogram> verify) throws IOException {
diff --git a/x-pack/plugin/src/test/resources/rest-api-spec/test/rollup/rollup_search.yml b/x-pack/plugin/src/test/resources/rest-api-spec/test/rollup/rollup_search.yml
index cc5b778223379..ca04327eab729 100644
--- a/x-pack/plugin/src/test/resources/rest-api-spec/test/rollup/rollup_search.yml
+++ b/x-pack/plugin/src/test/resources/rest-api-spec/test/rollup/rollup_search.yml
@@ -1246,9 +1246,7 @@ setup:
 
 ---
 "Search error against live index":
-  - skip:
-      version: "all"
-      reason:  "AwaitsFix: https://github.com/elastic/elasticsearch/issues/41970"
+
   - do:
       catch: bad_request
       rollup.rollup_search:
@@ -1264,9 +1262,7 @@ setup:
 
 ---
 "Search error against rollup and live index":
-  - skip:
-      version: "all"
-      reason:  "AwaitsFix: https://github.com/elastic/elasticsearch/issues/41970"
+
   - do:
       catch: bad_request
       rollup.rollup_search: