Navigate to http://localhost:11501 . Open DevTools (F12) → Network tab. Reload. Look for response headers that might reveal the server type (e.g., X-Powered-By: Express , Server: nginx ).
If you can provide more context (e.g., when you see this address, what error you’re getting, or what you were trying to do), I can give a more specific answer. localhost11501
—E.