diff --git a/lib/src/manager/im_message_manager.dart b/lib/src/manager/im_message_manager.dart
index 235b508..87849f1 100644
--- a/lib/src/manager/im_message_manager.dart
+++ b/lib/src/manager/im_message_manager.dart
@@ -564,7 +564,7 @@ class MessageManager {
             'conversationID': conversationID,
             'clientMsgID': clientMsgID,
             "operationID": Utils.checkOperationID(operationID),
-            'message': message,
+            'message': message.toJson(),
           }));
 
   /// Mark messages as read