diff --git a/twidere/src/main/kotlin/org/mariotaku/twidere/task/twitter/message/GetMessagesTask.kt b/twidere/src/main/kotlin/org/mariotaku/twidere/task/twitter/message/GetMessagesTask.kt
index 589b24727..6a3c41c49 100644
--- a/twidere/src/main/kotlin/org/mariotaku/twidere/task/twitter/message/GetMessagesTask.kt
+++ b/twidere/src/main/kotlin/org/mariotaku/twidere/task/twitter/message/GetMessagesTask.kt
@@ -510,7 +510,7 @@ class GetMessagesTask(
                     this.participants = participants + ParcelableUserUtils.fromUser(user, accountKey)
                 }
             }
-            participants.sortBy(ParcelableUser::screen_name)
+            this.participants.sortBy(ParcelableUser::screen_name)
         }
 
         private fun Map<String, List<ParcelableMessage>>.findLastReadTimestamp(conversationId: String, lastReadEventId: String?): Long {