diff --git a/opentech/storage_backends.py b/opentech/storage_backends.py
index 0e0bf2664f207f097b1306e02ca6c3e805dba7f5..4dba8b95e81bd05ce6dc79e6a4932e2e91d68428 100644
--- a/opentech/storage_backends.py
+++ b/opentech/storage_backends.py
@@ -27,7 +27,7 @@ class PrivateMediaStorage(S3Boto3Storage):
     encryption = True
     file_overwrite = False
     querystring_auth = True
-    secure_urls = True
+    url_protocol = 'https:'
 
     def url(self, name, parameters=None, expire=None):
         url = super().url(name, parameters, expire)