The Ultimate 'Connection Refused' Guide: A PHP PDO & Docker Debugging Saga of a Forgotten Port

A deep dive into a tricky PHP PDO `SQLSTATE[HY000] [2002] Connection refused` error. When MySQL Workbench connects perfectly but a PHP script in a Docker container fails, what's the real culprit? This article walks you through a complete troubleshooting journey, from user permissions, firewalls, and Docker networking, to uncovering the final issue: a missing port parameter in AI-generated code. This real-world case study from wiki.lib00.com on meticulous, systematic debugging will save you hours of future frustration.