Fix: ERR_CONNECTION_REFUSED (localhost refused to connect)
How to fix 'ERR_CONNECTION_REFUSED', 'localhost refused to connect', and 'This site can't be reached' errors when accessing localhost in Chrome, Firefox, and Edge. Covers dev servers, port issues, 0.0.0.0 vs 127.0.0.1, Docker port mapping, WSL2, firewalls, and more.