502 Bad Gateway nginx/1.24.0 502 Bad Gateway nginx/1.24.0 502 Bad Gateway nginx/1.24.0 2024/01/15 03:42:11 [error] 1234#1234: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 203.0.113.5, server: yourdomain.com, request: "GET / HTTP/1.1", upstream: "http://127.0.0.1:3000/", host: "yourdomain.com" 2024/01/15 03:42:11 [error] 1234#1234: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 203.0.113.5, server: yourdomain.com, request: "GET / HTTP/1.1", upstream: "http://127.0.0.1:3000/", host: "yourdomain.com" 2024/01/15 03:42:11 [error] 1234#1234: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 203.0.113.5, server: yourdomain.com, request: "GET / HTTP/1.1", upstream: "http://127.0.0.1:3000/", host: "yourdomain.com" # Check if your Node/Python/whatever process is alive ps aux | grep node ps aux | grep python ps aux | grep gunicorn # Or check what's listening on your port ss -tlnp | grep :3000 # Check if your Node/Python/whatever process is alive ps aux | grep node ps aux | grep python ps aux | grep gunicorn # Or check what's listening on your port ss -tlnp | grep :3000 # Check if your Node/Python/whatever process is alive ps aux | grep node ps aux | grep python ps aux | grep gunicorn # Or check what's listening on your port ss -tlnp | grep :3000 # If using PM2 pm2 logs --lines 50 # If using systemd journalctl -u your-app-name -n 50 --no-pager # If using Docker docker logs your-container-name --tail 50 # If using PM2 pm2 logs --lines 50 # If using systemd journalctl -u your-app-name -n 50 --no-pager # If using Docker docker logs your-container-name --tail 50 # If using PM2 pm2 logs --lines 50 # If using systemd journalctl -u your-app-name -n 50 --no-pager # If using Docker docker logs your-container-name --tail 50 # PM2 pm2 restart your-app # systemd sudo systemctl restart your-app # Watch logs as it starts pm2 logs --lines 0 # PM2 pm2 restart your-app # systemd sudo systemctl restart your-app # Watch logs as it starts pm2 logs --lines 0 # PM2 pm2 restart your-app # systemd sudo systemctl restart your-app # Watch logs as it starts pm2 logs --lines 0 # Verify your nginx config is correct sudo nginx -t # Check upstream address matches where your app runs grep -r "proxy_pass" /etc/nginx/sites-enabled/ # Verify your nginx config is correct sudo nginx -t # Check upstream address matches where your app runs grep -r "proxy_pass" /etc/nginx/sites-enabled/ # Verify your nginx config is correct sudo nginx -t # Check upstream address matches where your app runs grep -r "proxy_pass" /etc/nginx/sites-enabled/ # PM2 auto-restart config (ecosystem.config.js) module.exports = { apps: [{ name: 'your-app', script: 'server.js', max_restarts: 10, min_uptime: '10s', watch: false }] } # PM2 auto-restart config (ecosystem.config.js) module.exports = { apps: [{ name: 'your-app', script: 'server.js', max_restarts: 10, min_uptime: '10s', watch: false }] } # PM2 auto-restart config (ecosystem.config.js) module.exports = { apps: [{ name: 'your-app', script: 'server.js', max_restarts: 10, min_uptime: '10s', watch: false }] } # 1. Is app running? ss -tlnp | grep :3000 # 2. App logs pm2 logs --lines 50 # 3. nginx error log sudo tail -50 /var/log/nginx/error.log # 4. nginx config valid? sudo nginx -t # 5. Disk full? (apps crash silently when disk is full) df -h # 6. RAM full? free -h # 1. Is app running? ss -tlnp | grep :3000 # 2. App logs pm2 logs --lines 50 # 3. nginx error log sudo tail -50 /var/log/nginx/error.log # 4. nginx config valid? sudo nginx -t # 5. Disk full? (apps crash silently when disk is full) df -h # 6. RAM full? free -h # 1. Is app running? ss -tlnp | grep :3000 # 2. App logs pm2 logs --lines 50 # 3. nginx error log sudo tail -50 /var/log/nginx/error.log # 4. nginx config valid? sudo nginx -t # 5. Disk full? (apps crash silently when disk is full) df -h # 6. RAM full? free -h