Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

View list

Fix Nginx Upstream Connection Refused Socket Error

When Nginx returns a 502 Bad Gateway or logs upstream connection refused

How to Check Node Version Compatibility with a Package
You're about to install or update a package, and you see warnings like "requires Node.js ...

Cloudflare Error 521: Web Server Down Checklist
Cloudflare error 521 means your origin web server refused the connection. This is not a Cloudflar...

Docker Compose ENV Not Passed to Entrypoint: Fix
You define an environment variable in your docker-compose.yml, but when the containe...

Fix Git SSL Certificate Problem: Unable to Get Local Issuer
You try to clone or pull from a remote repository and get: fatal: unable to access 'htt...

Python Virtual Environment Not Activating: Common Fixes
You run source venv/bin/activate (or venv\Scripts\activate on Windows) ...

Checklists for software errors, setup, and tool workflows.

Latest checklists

Fix Nginx Upstream Connection Refused Socket Error

How to Check Node Version Compatibility with a Package

Cloudflare Error 521: Web Server Down Checklist

Docker Compose ENV Not Passed to Entrypoint: Fix

Fix Git SSL Certificate Problem: Unable to Get Local Issuer

Python Virtual Environment Not Activating: Common Fixes

`Topic paths`

`Quick titles`