diff --git a/apps/ops/celery/hmac_signed_serializer.py b/apps/ops/celery/hmac_signed_serializer.py
index 2fca6eefe6a..5a5cc85bdf3 100644
--- a/apps/ops/celery/hmac_signed_serializer.py
+++ b/apps/ops/celery/hmac_signed_serializer.py
@@ -5,7 +5,7 @@
 import uuid_utils.compat as uuid
 from kombu.serialization import register
 
-_local_secret_key = os.environ.get('MAXKB_HMAC_SIGNED_SERIALIZER_SECRET_KEY', os.getenv('MAXKB_SECRET_KEY', uuid.uuid7()))
+_local_secret_key = os.environ.get('MAXKB_HMAC_SIGNED_SERIALIZER_SECRET_KEY', os.getenv('MAXKB_SECRET_KEY', str(uuid.uuid7())))
 try:
     from xpack import get_md5
     _local_secret_key = get_md5()