diff --git a/setup_build_server.sh b/setup_build_server.sh
index 113f950..1292413 100755
--- a/setup_build_server.sh
+++ b/setup_build_server.sh
@@ -108,10 +108,10 @@ server {
     # Backend API
     location /api/ {
         proxy_pass http://127.0.0.1:8000;
-        proxy_set_header Host $host;
-        proxy_set_header X-Real-IP $remote_addr;
-        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
-        proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_set_header Host \$host;
+        proxy_set_header X-Real-IP \$remote_addr;
+        proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto \$scheme;
     }
 }
 EOL