1 files changed, 5 insertions, 3 deletions
diff --git a/synapse/handlers/relations.py b/synapse/handlers/relations.py
index 9b13448cdd..a15983afae 100644
--- a/synapse/handlers/relations.py
+++ b/synapse/handlers/relations.py
@@ -167,7 +167,7 @@ class RelationsHandler:
         now = self._clock.time_msec()
         serialize_options = SerializeEventConfig(requester=requester)
         return_value: JsonDict = {
-            "chunk": self._event_serializer.serialize_events(
+            "chunk": await self._event_serializer.serialize_events(
                 events,
                 now,
                 bundle_aggregations=aggregations,
@@ -177,7 +177,9 @@ class RelationsHandler:
         if include_original_event:
             # Do not bundle aggregations when retrieving the original event because
             # we want the content before relations are applied to it.
-            return_value["original_event"] = self._event_serializer.serialize_event(
+            return_value[
+                "original_event"
+            ] = await self._event_serializer.serialize_event(
                 event,
                 now,
                 bundle_aggregations=None,
@@ -602,7 +604,7 @@ class RelationsHandler:
         )
 
         now = self._clock.time_msec()
-        serialized_events = self._event_serializer.serialize_events(
+        serialized_events = await self._event_serializer.serialize_events(
             events, now, bundle_aggregations=aggregations
         )