Check for blocking operations, ensure your event loop is not overloaded, and review resource usage for bottlenecks.

If your Node.js application is not responding, it can severely impact user experience, so addressing the issue promptly is vital. Start by checking for any blocking operations in your code, as synchronous code can block the event loop and prevent your application from handling incoming requests. Review your use of asynchronous operations; if any are not properly managed, they may lead to unresponsiveness. Use profiling tools to monitor your event loop and check for overloads, which can indicate that your application is trying to handle too many concurrent requests or performing resource-intensive operations without yielding back to the event loop. Additionally, analyze your resource usage, including memory and CPU consumption, to identify any bottlenecks that may be causing the application to hang. Consider implementing rate limiting or load balancing if your application receives a high volume of requests that it cannot handle effectively. If possible, enable logging to capture any errors or warnings that occur during runtime, which can provide insight into what might be going wrong. By systematically examining these areas, you can effectively troubleshoot and resolve issues related to your Node.js application not responding.