diff --git a/frontend/nginx.conf b/frontend/nginx.conf
index 91d62b4..c212adb 100644
--- a/frontend/nginx.conf
+++ b/frontend/nginx.conf
@@ -4,9 +4,13 @@ server {
     root /usr/share/nginx/html;
     index index.html;
 
+    # DNS resolver for Docker
+    resolver 127.0.0.11 valid=30s;
+
     # API proxy
     location /api {
-        proxy_pass http://veridian-preview-backend:3000;
+        set $backend_upstream "veridian-preview-backend:3000";
+        proxy_pass http://$backend_upstream;
         proxy_http_version 1.1;
         proxy_set_header Upgrade $http_upgrade;
         proxy_set_header Connection 'upgrade';