diff --git a/docker/frontend/nginx.conf b/docker/frontend/nginx.conf
index 82ba1f415..c5832eb5c 100644
--- a/docker/frontend/nginx.conf
+++ b/docker/frontend/nginx.conf
@@ -6,6 +6,11 @@ http {
     include /etc/nginx/mime.types;
     default_type application/octet-stream;
 
+    # Add .mjs MIME type mapping
+    types {
+        text/javascript mjs;
+    }
+
     # Gzip compression
     gzip on;
     gzip_vary on;
@@ -92,7 +97,8 @@ http {
 
         # Serve .mjs files with correct MIME type (must come before general static assets)
         location ~* \.mjs$ {
-            add_header Content-Type text/javascript;
+            try_files $uri =404;
+            add_header Content-Type "text/javascript; charset=utf-8" always;
             expires 1y;
             add_header Cache-Control "public, immutable";
         }