diff --git a/deploy/nginx-m1.conf b/deploy/nginx-m1.conf
index d086807..7a28f6c 100644
--- a/deploy/nginx-m1.conf
+++ b/deploy/nginx-m1.conf
@@ -4,6 +4,9 @@ server {
     root /usr/share/nginx/html;
     index index.html;
 
+    # Docker embedded DNS for service name resolution (fastapi)
+    resolver 127.0.0.11 valid=10s;
+
     # SPA: fall back to index.html for any path
     # Proxy API calls to the FastAPI backend (M3+)
     # Use variable to defer DNS resolution (docker service name "fastapi")