Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

You install or update a Chrome extension, but it refuses to load. Instead, you see a Perm...

Fix Windows Defender Real-Time Protection Not Running
You open Windows Security and see a yellow warning: "Real-time protection is off." Or you...

Fix Nginx Upstream Connection Refused Error
When Nginx returns upstream connection refused in your error logs, it means Nginx tr...

Fix Cloudflare Error 521 After a Server Update
If you see Cloudflare error 521 after updating your server, the origin web server is refusing the...

How to Fix Git Push Rejected (Non-Fast-Forward) Error
You run git push and get an error like ! [rejected] main -> main (non-fast-...

How to Fix an Nginx Redirect Loop: Step-by-Step You load a site and the browser keeps spinning—eventually showing 'redirect loop' or '...