Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

If Firefox shows a “Secure Connection Failed” error and won’t let you load a site, it usually mea...

When you run npm install or npm start and see npm ERR! package.js...

Docker Compose .env File Not Loading: Common Fixes
You set environment variables in a .env file next to your docker-compose.yml

Fix Cloudflare 521 Error Due to Server Overload
You see a Cloudflare 521 error page. The message says the web server is down. Often, this means y...

Checklist to Fix npm Permission Denied Errors
If you see "EACCES: permission denied" or "Error: EACCES, mkdir" when running npm...

Fixing Cloudflare Wildcard Subdomain Proxy Errors
If you've set up a wildcard DNS record (e.g., *.example.com) in Cloudflare and a...