diff --git a/conf/old.nginx.conf b/conf/old.nginx.conf
index 620f6bf..da97825 100644
--- a/conf/old.nginx.conf
+++ b/conf/old.nginx.conf
@@ -92,7 +92,7 @@ location ~ ^/api/.*$ {
 location ~ ^/(blob|block)/.*$ {
     if ($request_method = 'OPTIONS') {
         more_set_headers "Access-Control-Allow-Origin: ${allowed_origins}";
-        more_set_headers add_header "Access-Control-Allow-Credentials: true";
+        more_set_headers "Access-Control-Allow-Credentials: true";
         more_set_headers "Access-Control-Allow-Methods: 'GET, POST, OPTIONS'";
         more_set_headers "Access-Control-Allow-Headers: DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range";
         more_set_headers "Access-Control-Max-Age: 1728000";