NGINX is a versatile open-source software used in modern web infrastructure, known for its speed, stability, and low resource consumption, making it ideal for high-traffic websites and applications. It functions as a web server, reverse proxy, load balancer, and HTTP cache, but can encounter errors that lead to downtime, poor user experiences, and security vulnerabilities. Common NGINX errors include configuration mistakes, resource limitations, network issues, permission problems, and upstream server errors like 502 Bad Gateway and 503 Service Unavailable. Troubleshooting involves checking server status and error logs, analyzing HTTP status codes, and verifying configurations. Prevention strategies include thorough configuration testing, regular log monitoring, resource monitoring, keeping NGINX updated, and performing backend server health checks. Tools like New Relic's NGINX performance monitoring integration offer insights and metrics to enhance performance and error management.