diff --git a/src/libstore/s3-binary-cache-store.cc b/src/libstore/s3-binary-cache-store.cc
index 06622210c..145a8191c 100644
--- a/src/libstore/s3-binary-cache-store.cc
+++ b/src/libstore/s3-binary-cache-store.cc
@@ -79,7 +79,7 @@ static void initAWS()
 
 S3Helper::S3Helper(const string & region)
     : config(makeConfig(region))
-    , client(make_ref<Aws::S3::S3Client>(*config))
+    , client(make_ref<Aws::S3::S3Client>(*config, true, false))
 {
 }