fix(startup): use stable internal service addresses (#6721)

nginx.conf

@@ -9,7 +9,7 @@ http {
 
         # Route websockets traffic to port 3001
         location /websockets {
-            proxy_pass http://${HOSTNAME}:3001;
+            proxy_pass http://127.0.0.1:3001;
             proxy_http_version 1.1;
             proxy_set_header Upgrade $http_upgrade;
             proxy_set_header Connection "Upgrade";
@@ -18,7 +18,7 @@ http {
 
         # Route all other traffic to port 3000
         location / {
-            proxy_pass http://${HOSTNAME}:3000;
+            proxy_pass http://127.0.0.1:3000;
             proxy_set_header Host $http_host;
             proxy_set_header X-Real-IP $remote_addr;
             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;