Troubleshooting:Nginx Troubleshooting

Note: Public HTTPS on this VPS is handled by Caddy (/etc/caddy/Caddyfile). Use System:Service Management and journalctl -u caddy for edge proxy issues.

This guide covers legacy host Nginx site files and the WebApp stack's internal Nginx container. Host Nginx is not the active edge proxy for *.jb-vpn.uk services.

Configuration Errors

Syntax Errors

Symptoms: nginx -t fails with syntax errors

Solutions:

Check for missing semicolons

Verify bracket matching

Check for typos in directive names

Duplicate Server Names

Symptoms: Warning about duplicate server_name

Solutions:

Check all configuration files in /etc/nginx/sites-enabled/

Remove duplicate server_name entries

Ensure only one config per subdomain

Service Issues

Nginx Won't Start

Check status:

   systemctl status nginx

Check logs:

   journalctl -u nginx -n 50

Test configuration:

   nginx -t

Nginx Reload Fails

Test configuration first:

   nginx -t

Check for syntax errors in configuration files

Verify file permissions:

   ls -la /etc/nginx/sites-enabled/

Log Analysis

Error Logs

==== View recent errors ====
tail -f /var/log/nginx/error.log

== Search for specific errors ==
grep "error" /var/log/nginx/error.log

Access Logs

==== View recent access ====
tail -f /var/log/nginx/access.log

== Analyze traffic ==
awk '{print $1}' /var/log/nginx/access.log | sort | uniq -c | sort -rn

Common Configuration Issues

SSL Certificate Problems

Verify certificate exists: certbot certificates

Check certificate expiration: openssl x509 -in /etc/letsencrypt/live/domain/cert.pem -noout -dates

Renew if needed: certbot renew

Proxy Issues

Check proxy_pass URL is correct

Verify target service is accessible

Check proxy headers are set correctly