#ECONNREFUSED

ECONNREFUSED: Connection Refused — 5 Causes Explained (Including Docker)

Node, Java, or curl reporting connect ECONNREFUSED 127.0.0.1:3306? It means nothing is listening on that port. Covers service not running, wrong port, 127.0.0.1-only binding, Docker container networking, and firewall REJECT rules — with ss/lsof diagnostic commands.