diff --git a/lambda/main.py b/lambda/main.py
index b927602..4a453a9 100644
--- a/lambda/main.py
+++ b/lambda/main.py
@@ -161,12 +161,18 @@ def bad_data_save(data: list, reason: str):
         key += str(uuid.uuid4()) + ".gz"
 
         logger.info(f"Saving failed records to S3: s3://{FAILED_LOG_S3_BUCKET}/{key}")
-        data = '\n'.join(str(f) for f in data)
+        data = '\n'.join(to_str(f) for f in data)
         put_to_s3(key, FAILED_LOG_S3_BUCKET, data)
 
         xray_recorder.end_subsegment()
 
 
+def to_str(a):
+    if type(a) == dict:
+        return json.dumps(a)
+    return a
+
+
 # noinspection PyUnusedLocal
 def handler(event, context):
     raw_records = event['Records']