Knowledge base for software setup, errors, and daily tool work.

Fix Docker Nginx 502 Bad Gateway Upstream Error

When running Nginx as a reverse proxy in Docker, a 502 Bad Gateway error with 'upstream' ...

Firefox Secure Connection Failed: How to Fix

When Firefox shows 'Secure Connection Failed' or similar warnings like 'PR_END_OF_FIL...

Fix 'package.json Not Found' After Cloning a Repository

Symptom

You clone a repository from GitHub (or another remote), change into the directory...

Fixing Cloudflare 521 Error: Origin Unreachable

When you see Cloudflare error 521, it means your origin server is refusing the connection from Cl...

Chrome Certificate Error: Not Secure Site Workaround

You're trying to reach a site and Chrome shows a full-page warning: “Your connection is not p...

Chrome Certificate Error Invalid Authority: Diagnosis Checklist

When Chrome shows NET::ERR_CERT_AUTHORITY_INVALID and refuses to load a site, it...