SonarQube Starting Issues
SonarQube uses 9000 for its web UI. It often fails if ElasticSearch (part of Sonar) hasn't initialized yet.
1. Check Logs
SonarQube logs are in /logs/sonar.log. Wait for "SonarQube is up" message before accessing port 9000.
2. PHP-FPM Conflict
On some Linux setups, PHP-FPM also uses port 9000. Check configuration in /etc/php/fpm/pool.d/www.conf.
